# gemmology.dev

> Open, FGA-aligned reference and study toolkit for coloured gemstones. Free and open-source.

## Core surfaces
- [Home](https://gemmology.dev/): Project overview, mineral counts, calculators.
- [Mineral gallery](https://gemmology.dev/gallery/): Browse all 303 mineral pages with crystal SVGs.
- [Learn hub](https://gemmology.dev/learn/): 138 curriculum-aligned articles across crystallography, optics, identification, and species.
- [CDL specification](https://gemmology.dev/docs/cdl/): Crystal Description Language v2 reference.
- [API reference](https://gemmology.dev/docs/api/cdl-parser/): Python package APIs.
- [About](https://gemmology.dev/about/): Editorial standards, sourcing, licensing.

## Learn

### Fundamentals
- [Crystal Systems](https://gemmology.dev/learn/fundamentals/crystal-systems): The seven crystal systems and their characteristic symmetry elements.
- [Advanced Crystallography](https://gemmology.dev/learn/fundamentals/crystallography-advanced): Twinning, Miller indices, crystal habits, crystal forms, point groups, and crystal growth mechanisms.
- [Twin Laws in Gemmology](https://gemmology.dev/learn/fundamentals/twin-laws): Named twin laws – spinel, Carlsbad, Manebach, Baveno, albite, pericline, Brazil, Dauphiné, Japan – and corundum parting, with diagnostic applications.
- [Physical Properties](https://gemmology.dev/learn/fundamentals/physical-properties): Hardness, specific gravity, cleavage, fracture, and lustre.
- [Chemical Properties](https://gemmology.dev/learn/fundamentals/chemical-properties): Gem chemistry, chromophores and colour causes, allochromatic vs idiochromatic minerals, charge transfer, and colour centres.
- [Optical Properties](https://gemmology.dev/learn/fundamentals/optical-properties): Refractive index, birefringence, pleochroism, dispersion, and other optical properties of gemstones.
- [Colour Theory in Gemmology](https://gemmology.dev/learn/fundamentals/colour-theory): The physics and chemistry of gem colour: crystal field theory, charge transfer, colour centres, allochromatic and idiochromatic minerals, and band-gap colouration.
- [Advanced Optical Properties](https://gemmology.dev/learn/fundamentals/optical-properties-advanced): Interference figures, optic sign determination, complete absorption spectra, luminescence, and anomalous double refraction.
- [Optic Sign Determination](https://gemmology.dev/learn/fundamentals/optic-sign-determination): Determining positive or negative optic sign for uniaxial and biaxial gems using the refractometer, lambda plate, and interference figures.

### Equipment
- [Gem Testing Equipment Overview](https://gemmology.dev/learn/equipment/overview): Introduction to gemmological instruments, testing workflow, and which tool to use for different identification tasks.
- [The Refractometer](https://gemmology.dev/learn/equipment/refractometer): Refractive index measurement using the gemmological refractometer, including faceted and cabochon techniques, birefringence reading, and troubleshooting.
- [The Polariscope](https://gemmology.dev/learn/equipment/polariscope): Using the polariscope to determine optic character (isotropic vs anisotropic), detect anomalous double refraction, and observe interference figures.
- [The Dichroscope](https://gemmology.dev/learn/equipment/dichroscope): Using the dichroscope to observe pleochroism in coloured gemstones, distinguishing dichroic from trichroic materials.
- [The Spectroscope](https://gemmology.dev/learn/equipment/spectroscope): Using the spectroscope to observe absorption spectra, identifying characteristic patterns for gem species and detecting treatments.
- [The Microscope](https://gemmology.dev/learn/equipment/microscope): Using the gemmological microscope for inclusion study, illumination techniques, and immersion methods to identify gems and detect treatments.
- [The UV Lamp](https://gemmology.dev/learn/equipment/uv-lamp): Using ultraviolet light for fluorescence testing, distinguishing LWUV from SWUV reactions, and safety considerations.
- [Other Testing Tools](https://gemmology.dev/learn/equipment/other-tools): Chelsea filter, thermal conductivity probes, specific gravity measurement, and other supporting gemmological instruments.
- [Chelsea Colour Filter](https://gemmology.dev/learn/equipment/chelsea-colour-filter): Using the Chelsea Colour Filter as a chromium discriminator for gem identification – including the species reaction table, lighting requirements, and diagnostic limitations.
- [Specific Gravity Measurement](https://gemmology.dev/learn/equipment/sg-measurement): Hydrostatic weighing and heavy-liquid methods for measuring specific gravity – the density-based property used to identify and confirm gem species.
- [Conoscopic Observation and Interference Figures](https://gemmology.dev/learn/equipment/conoscope): Using convergent polarised light to observe interference figures that reveal a gemstone's optic character (uniaxial or biaxial) and optic sign – an advanced polariscope technique.
- [Advanced Laboratory Instruments](https://gemmology.dev/learn/equipment/advanced-lab-instruments): Diploma-level awareness of FTIR, UV-Vis-NIR, Raman, EDXRF, LA-ICP-MS, and photoluminescence spectroscopy – what each detects and its key gemmological applications.
- [Diamond Screening Instruments](https://gemmology.dev/learn/equipment/diamond-screening): Thermal conductivity probes, electrical conductivity testers, DiamondView, DiamondSure, and reflectance meters – the tools used to screen loose diamonds and detect synthetic and simulant materials.

### Species
- [Corundum](https://gemmology.dev/learn/species/corundum): Corundum species including ruby and sapphire varieties, properties, inclusions, origins, treatments, and historical significance.
- [Beryl](https://gemmology.dev/learn/species/beryl): Beryl species including emerald, aquamarine, morganite, heliodor, goshenite, and red beryl with properties, inclusions, and treatments.
- [Garnet Group](https://gemmology.dev/learn/species/garnet): The garnet group minerals including almandine, pyrope, spessartine, grossular, andradite, and their gem varieties like demantoid and tsavorite.
- [Tourmaline Group](https://gemmology.dev/learn/species/tourmaline): The tourmaline group including elbaite varieties (rubellite, indicolite, Paraíba), dravite, and chrome tourmaline with properties and identification.
- [Spinel](https://gemmology.dev/learn/species/spinel): Spinel species including red, blue, pink, and colour-change varieties with properties, origins, historical significance, and identification.
- [Topaz](https://gemmology.dev/learn/species/topaz): Topaz species including imperial, blue, sherry, and colourless varieties with properties, treatments, and identification.
- [Quartz](https://gemmology.dev/learn/species/quartz): Quartz species including amethyst, citrine, rose quartz, smoky quartz, rock crystal, and chalcedony varieties with properties and identification.
- [Feldspar Group](https://gemmology.dev/learn/species/feldspar): Feldspar group gems including moonstone, labradorite, sunstone, amazonite, and orthoclase with properties, phenomena, and identification.
- [Chrysoberyl](https://gemmology.dev/learn/species/chrysoberyl): Chrysoberyl species including alexandrite and cat's eye chrysoberyl (cymophane) with properties, colour change, chatoyancy, and identification.
- [Zircon](https://gemmology.dev/learn/species/zircon): Zircon species including blue, colourless, and fancy colours with metamict types, properties, treatments, and identification.
- [Olivine (Peridot)](https://gemmology.dev/learn/species/olivine): Olivine species and its gem variety peridot with properties, characteristic inclusions, sources, and identification.
- [Zoisite](https://gemmology.dev/learn/species/zoisite): Zoisite species including tanzanite, thulite, and anyolite with properties, colour change, treatments, and identification.
- [Diamond](https://gemmology.dev/learn/species/diamond): Diamond type classification, the 4Cs grading system, fancy colours, natural vs lab-grown identification, and diamond verification instruments.
- [Pyroxene Group](https://gemmology.dev/learn/species/pyroxene): Pyroxene group gems including jadeite, spodumene (kunzite, hiddenite), and diopside (chrome diopside) with properties and identification.
- [Amphibole Group (Nephrite)](https://gemmology.dev/learn/species/amphibole): Amphibole group gems, primarily nephrite jade, with properties, comparison to jadeite, sources, and identification.
- [Opal](https://gemmology.dev/learn/species/opal): Opal species including precious opal (black, white, crystal, boulder, fire) and common opal with play of colour, patterns, and identification.
- [Pearl](https://gemmology.dev/learn/species/pearl): Pearl formation, types (natural, Akoya, South Sea, Tahitian, freshwater), grading factors, identification, and care.
- [Coral](https://gemmology.dev/learn/species/coral): Precious coral species including red (ox blood), pink (angel skin), and related varieties with identification, treatments, and conservation.
- [Amber](https://gemmology.dev/learn/species/amber): Amber fossilised tree resin including Baltic, Dominican, and Burmese varieties with inclusions, identification, and distinguishing from copal.
- [Jet](https://gemmology.dev/learn/species/jet): Jet fossilised wood including Whitby jet, properties, Victorian significance, identification, and distinguishing from simulants.

### Identification
- [Beryllium Diffusion – Deep Diagnostic Reference](https://gemmology.dev/learn/identification/treatments-deep/beryllium-diffusion): Full per-method detection protocol for beryllium lattice diffusion in corundum, with disclosure standards and stability data.
- [Inclusions Overview](https://gemmology.dev/learn/identification/inclusions/overview): Introduction to inclusions, their classification, and microscopy techniques for examination.
- [Lead Glass-Filled Ruby – Deep Diagnostic Reference](https://gemmology.dev/learn/identification/treatments-deep/lead-glass-ruby): Full detection protocol for composite (lead glass-filled) ruby, with nomenclature, durability, and disclosure standards.
- [Solid Inclusions](https://gemmology.dev/learn/identification/inclusions/solid-inclusions): Crystal inclusions - identifying mineral guests trapped within gemstones during formation.
- [HPHT Diamond Treatment – Deep Diagnostic Reference](https://gemmology.dev/learn/identification/treatments-deep/hpht-diamond): Full detection protocol for HPHT-treated natural diamonds, including type-by-type outcomes, DiamondView patterns, and photoluminescence signatures.
- [Fluid Inclusions](https://gemmology.dev/learn/identification/inclusions/fluid-inclusions): Two-phase, three-phase, and negative crystal inclusions - trapped fluids that reveal formation conditions.
- [CVD Diamond Detection – Deep Diagnostic Reference](https://gemmology.dev/learn/identification/treatments-deep/cvd-diamond): Full detection protocol for CVD synthetic diamonds, distinguishing from natural and HPHT-treated stones using DiamondView, FTIR, and photoluminescence.
- [Growth Features](https://gemmology.dev/learn/identification/inclusions/growth-features): Colour zoning, growth tubes, twinning, phantoms, and other patterns formed during crystallization.
- [Gemstone Treatments](https://gemmology.dev/learn/identification/treatments): Heat treatment, filling, diffusion, coating, and detection methods for treated gemstones – with per-species diagnostic depth.
- [Feathers & Fingerprints](https://gemmology.dev/learn/identification/inclusions/feathers): Healed fractures, fingerprint inclusions, and liquid feathers - characteristic healing patterns in gems.
- [Synthetic Gemstones](https://gemmology.dev/learn/identification/synthetics): Synthetic gem production methods including flame fusion, hydrothermal, flux growth, and detection techniques.
- [Silk & Needle Inclusions](https://gemmology.dev/learn/identification/inclusions/silk): Rutile silk, needle inclusions, and their role in asterism and origin determination.
- [Natural vs Synthetic Indicators](https://gemmology.dev/learn/identification/inclusions/natural-vs-synthetic): Distinguishing natural gemstones from synthetics using inclusion evidence.
- [Surface Features](https://gemmology.dev/learn/identification/inclusions/surface-features): Naturals, bearding, etch channels, and other surface-related inclusion features.
- [Composite Stones](https://gemmology.dev/learn/identification/composite-stones): Doublets, triplets, assembled stones, and their detection including opal doublets, garnet-topped doublets, and soudé emeralds.

### Phenomena
- [Optical Phenomena Overview](https://gemmology.dev/learn/phenomena/overview): Introduction to optical phenomena in gemstones including light interaction principles and summary of major phenomena.
- [Asterism (Star Effect)](https://gemmology.dev/learn/phenomena/asterism): Asterism in gemstones including star ruby, star sapphire, and other star stones with formation, quality factors, and identification.
- [Chatoyancy (Cat's Eye Effect)](https://gemmology.dev/learn/phenomena/chatoyancy): Chatoyancy in gemstones including chrysoberyl cat's eye, the milk and honey effect, and other chatoyant gems.
- [Adularescence](https://gemmology.dev/learn/phenomena/adularescence): Adularescence in moonstone including cause, types of moonstone, quality factors, and distinction from labradorescence.
- [Labradorescence](https://gemmology.dev/learn/phenomena/labradorescence): Labradorescence in labradorite and spectrolite including cause, colour range, quality factors, and distinction from adularescence.
- [Play of Colour](https://gemmology.dev/learn/phenomena/play-of-colour): Play of colour in precious opal including cause, pattern types, body tones, and quality assessment.
- [Colour Change](https://gemmology.dev/learn/phenomena/colour-change): Colour change phenomenon in gemstones including alexandrite, colour-change garnet, sapphire, and diaspore with causes and grading.
- [Aventurescence](https://gemmology.dev/learn/phenomena/aventurescence): Aventurescence in gemstones including sunstone and aventurine quartz with causes, types, and quality factors.
- [Iridescence](https://gemmology.dev/learn/phenomena/iridescence): Iridescence in gemstones including fire agate, ammolite, iris quartz, and surface coatings with causes and identification.
- [Schiller and Peristerescence](https://gemmology.dev/learn/phenomena/schiller): Schiller and peristerescence in feldspar – the mechanism of non-spectral lamellar scattering, named species, and distinction from adularescence, labradorescence, aventurescence, and chatoyancy.
- [Silk Effect](https://gemmology.dev/learn/phenomena/silk-effect): The silk effect in Kashmir sapphire and Burmese ruby – velvety appearance from rutile-needle clouds, mechanism, distinction from asterism, and diagnostic significance for origin and heat-treatment detection.
- [Fluorescence and Phosphorescence](https://gemmology.dev/learn/phenomena/fluorescence): Fluorescence and phosphorescence in gemstones – Stokes shift mechanism, LWUV vs SWUV regimes, species reaction table, phosphorescence afterglow, and diagnostic applications for natural vs synthetic identification.
- [Fire and Dispersion](https://gemmology.dev/learn/phenomena/fire-dispersion): Fire in faceted gemstones – dispersion as differential refraction by wavelength, the B–G interval, named dispersion values, relationship to facet design, and distinction from diffraction-based spectral effects.
- [Pearl Orient](https://gemmology.dev/learn/phenomena/orient): Pearl orient – the soft iridescent surface bloom of fine nacre, arising from thin-film diffraction and interference at aragonite tablet layers, distinguished from body colour, lustre, and fluorescence.
- [Tenebrescence](https://gemmology.dev/learn/phenomena/tenebrescence): Tenebrescence – reversible photochromic colour change in hackmanite driven by S₂⁻ radical colour centres, mechanism, named species, and diagnostic distinction from the alexandrite effect and irradiation-induced colour changes.
- [Alexandrite Effect – Physical Mechanism](https://gemmology.dev/learn/phenomena/alexandrite-effect): Deep dive into the alexandrite effect – Cr³⁺ in trigonal crystal field, the dual transmission window, photopic peak balance, named species including garnets, sapphire, and synthetic spinel, and how to test colour change under standardised illuminants.

### Origin
- [Origin Determination Overview](https://gemmology.dev/learn/origin/overview): Introduction to geographic origin determination for gemstones including methodology, premium factors, and laboratory reports.
- [Afghanistan – Gem Origins Overview](https://gemmology.dev/learn/origin/afghanistan/overview): Hindu Kush gem province – lapis lazuli (Sar-e-Sang), Panjshir emerald, Nuristan kunzite; multiple geological settings; conflict and artisanal mining context.
- [Australian Gems - Overview](https://gemmology.dev/learn/origin/australia/overview): Introduction to Australia's gem production, world leadership in opal, and significant sapphire and chrysoprase deposits.
- [Brazilian Gems - Overview](https://gemmology.dev/learn/origin/brazil/overview): Introduction to Brazil's diverse gem production including Paraíba tourmaline, imperial topaz, aquamarine, and other varieties.
- [Burmese Gems - Overview](https://gemmology.dev/learn/origin/burma/overview): Introduction to Myanmar's legendary gem production from Mogok and other regions, including ethical considerations.
- [East African Gems - Overview](https://gemmology.dev/learn/origin/east-africa/overview): Introduction to East Africa's emergence as a major coloured gem region, covering Tanzania, Kenya, and Mozambique.
- [Madagascar Gems - Overview](https://gemmology.dev/learn/origin/madagascar/overview): Introduction to Madagascar's emergence as a major gem source and its diverse production of sapphire, ruby, and rare species.
- [Pakistan – Gem Origins Overview](https://gemmology.dev/learn/origin/pakistan/overview): Himalayan collision zone gem deposits – Swat emerald, Hunza ruby, Katlang topaz, Skardu aquamarine; multiple geological settings.
- [Russia – Ural Gem Deposits Overview](https://gemmology.dev/learn/origin/russia/overview): Ural Mountains gem belt – demantoid garnet, alexandrite, emerald; Yakutia diamond; serpentinite and mica-schist geological settings.
- [Thailand – Gem Origins Overview](https://gemmology.dev/learn/origin/thailand/overview): Southeast Asian gem province centred on Chanthaburi, Trat, Kanchanaburi, Bo Phloi, and Bo Rai; world leader in corundum heat treatment and trading.
- [USA – Gem Origins Overview](https://gemmology.dev/learn/origin/usa/overview): US gem deposits – Montana sapphire, Utah red beryl, Arizona peridot, California and Maine tourmaline; geologically diverse patchwork provinces.
- [Kashmir Sapphire](https://gemmology.dev/learn/origin/kashmir): Kashmir sapphire characteristics, diagnostic inclusions, velvety appearance, historical significance, and market premiums.
- [Lapis Lazuli – Sar-e-Sang, Afghanistan](https://gemmology.dev/learn/origin/afghanistan/lapis): Sar-e-Sang (Badakhshan) lapis lazuli – the canonical ancient-world source, >7,000 years of continuous mining, geochemical fingerprinting, grades and quality.
- [Lightning Ridge Black Opal](https://gemmology.dev/learn/origin/australia/black-opal): The world's most valuable opal from Lightning Ridge, NSW - body tone, patterns, and quality factors.
- [Paraíba Tourmaline](https://gemmology.dev/learn/origin/brazil/paraiba): Brazil's legendary copper-bearing tourmaline - discovery, neon colours, and its position as the most valuable tourmaline.
- [Burmese Ruby](https://gemmology.dev/learn/origin/burma/ruby): Mogok and Mong Hsu ruby - the pigeon blood standard, diagnostic inclusions, and comparison with other sources.
- [Tanzanite](https://gemmology.dev/learn/origin/east-africa/tanzanite): Tanzania's signature gemstone from the Merelani Hills - single-source rarity, colour grades, and heat treatment.
- [Madagascar Sapphire](https://gemmology.dev/learn/origin/madagascar/sapphire): Ilakaka sapphire region - characteristics, Ceylon comparison, diagnostic inclusions, and quality assessment.
- [Swat Valley Emerald – Pakistan](https://gemmology.dev/learn/origin/pakistan/emerald): Ophiolite-hosted Cr-rich emerald from Mingora, Swat Valley; three-phase fluid inclusions, chromian muscovite, low Li chemistry, talc-carbonate paragenesis.
- [Russian Demantoid Garnet – Ural Mountains](https://gemmology.dev/learn/origin/russia/demantoid): Ural demantoid (andradite, Cr-coloured); horsetail inclusions – byssolite terminology and Kissin 2021 mineralogical correction; LA-ICP-MS origin discrimination from Namibia and Madagascar.
- [Thai Ruby – Chanthaburi-Trat and Bo Rai Types](https://gemmology.dev/learn/origin/thailand/ruby): Basaltic-hosted Siam ruby from Chanthaburi-Trat and Bo Rai; diagnostic high-Fe chemistry, 451/460/470 nm iron triplet, weak fluorescence, alluvial habit.
- [Montana Sapphire – Yogo Gulch, Rock Creek, Missouri River](https://gemmology.dev/learn/origin/usa/montana-sapphire): Yogo Gulch steely-blue lamprophyre sapphire (no heat needed), Rock Creek and Missouri River alluvial pastels; distinct Fe/Ti/Mg trace element chemistry; US commercial significance.
- [Panjshir Emerald – Afghanistan](https://gemmology.dev/learn/origin/afghanistan/emerald): Hydrothermal-sediment hosted Panjshir emerald; high Fe UV-Vis bands, low Li, three-phase inclusions in black shale context; distinction from Colombian.
- [Queensland Boulder Opal](https://gemmology.dev/learn/origin/australia/boulder-opal): Australian boulder opal with ironstone matrix backing - sources, patterns, and assessment criteria.
- [Brazilian Emerald](https://gemmology.dev/learn/origin/brazil/emerald): Brazilian emerald characteristics, comparison with Colombian material, and market position.
- [Burmese Sapphire](https://gemmology.dev/learn/origin/burma/sapphire): Mogok sapphire characteristics, inclusions, and market position relative to Kashmir and Ceylon.
- [Tsavorite Garnet](https://gemmology.dev/learn/origin/east-africa/tsavorite): East Africa's finest green garnet from Kenya and Tanzania - discovery, characteristics, and comparison with emerald.
- [Madagascar Ruby](https://gemmology.dev/learn/origin/madagascar/ruby): Ruby from Andilamena and other regions - characteristics, heat treatment, beryllium diffusion concerns.
- [Hunza Ruby – Pakistan](https://gemmology.dev/learn/origin/pakistan/ruby): Marble-hosted ruby from Hunza/Gilgit-Baltistan; low-Fe high-Cr chemistry analogous to Mogok; marble-suite inclusions; strong LWUV fluorescence.
- [Russian Alexandrite – Tokovaya District, Ural Mountains](https://gemmology.dev/learn/origin/russia/alexandrite): Tokovaya district alexandrite – 1830 discovery, named for Tsar Alexander II; benchmark colour change; mica-schist host; market position vs synthetic.
- [Thai Sapphire – Bo Phloi and Kanchanaburi Types](https://gemmology.dev/learn/origin/thailand/sapphire): Basaltic high-Fe blue sapphire from Bo Phloi and Kanchanaburi; strong 450/460/470 nm iron triplet, common heat treatment, basalt-suite inclusions.
- [Utah Red Beryl – Wah Wah Mountains](https://gemmology.dev/learn/origin/usa/utah-red-beryl): World's only commercial red beryl source – Mn³⁺-coloured beryl in Eocene topaz rhyolite, Wah Wah Mountains, Utah; properties, inclusions, market rarity.
- [Sri Lankan (Ceylon) Gems](https://gemmology.dev/learn/origin/ceylon): Sri Lankan sapphire, padparadscha, spinel, and other gems with characteristics, inclusions, and historical significance.
- [White Opal & Crystal Opal](https://gemmology.dev/learn/origin/australia/white-opal): Coober Pedy white opal and Australian crystal opal varieties - characteristics, quality grades, and market position.
- [Brazilian Aquamarine & Topaz](https://gemmology.dev/learn/origin/brazil/aquamarine): World-renowned Brazilian aquamarine including Santa Maria quality, and exclusive imperial topaz from Ouro Preto.
- [Burmese Spinel](https://gemmology.dev/learn/origin/burma/spinel): Mogok spinel - historic confusion with ruby, exceptional red and pink colours, and growing collector interest.
- [East African Ruby](https://gemmology.dev/learn/origin/east-africa/ruby): Ruby from Mozambique (Montepuez) and Kenya (John Saul Mine) - characteristics, inclusions, and market significance.
- [Madagascar Beryl](https://gemmology.dev/learn/origin/madagascar/beryl): Aquamarine, morganite, and limited emerald production from Madagascar - characteristics and market position.
- [Katlang Pink Topaz – Pakistan](https://gemmology.dev/learn/origin/pakistan/topaz): Chromium-coloured pink to champagne topaz from Katlang, Mardan district; Cr³⁺ colouring diagnostic, calcite-vein hosted, rare among topaz globally.
- [Ural Emerald – Malyshevsky, Russia](https://gemmology.dev/learn/origin/russia/emerald): Ural emerald from the Malyshevsky/Izumrudnye Kopi deposit; phlogopite mica inclusions diagnostic; Cr+V chromophores; mica-schist contact zone genesis.
- [Thai Blue Zircon – Heat-Treatment Hub](https://gemmology.dev/learn/origin/thailand/zircon): Thailand as the global centre for heat-treating Cambodian and Vietnamese zircon rough into blue zircon; origin, treatment process, and identification.
- [Colombian Emerald](https://gemmology.dev/learn/origin/colombia): Colombian emerald from Muzo, Chivor, and Coscuez with three-phase inclusions, characteristics, and market position.
- [Australian Sapphire](https://gemmology.dev/learn/origin/australia/sapphire): Australian sapphire characteristics including parti-sapphires, dark blues, and comparison with Asian sources.
- [Brazilian Tourmaline](https://gemmology.dev/learn/origin/brazil/tourmaline): Brazilian tourmaline varieties beyond Paraíba - rubellite, indicolite, chrome tourmaline, and other colours.
- [Burmese Jadeite](https://gemmology.dev/learn/origin/burma/jadeite): Imperial jade from Myanmar's Kachin State - the world's finest jadeite, characteristics, and the Asian market.
- [Mahenge Spinel](https://gemmology.dev/learn/origin/east-africa/spinel): Tanzania's exceptional neon pink to red spinel from the Mahenge region - discovery, characteristics, and market impact.
- [Rare Madagascar Gems](https://gemmology.dev/learn/origin/madagascar/rare-gems): Grandidierite, demantoid garnet, tourmaline, and other rare species from Madagascar's diverse geology.
- [Colombian Emerald Mines – Sub-Distinctions](https://gemmology.dev/learn/origin/colombia-mines): Mine-level diagnostics for Muzo (parisite + halite), Chivor (pyrite dominant), Coscuez, La Pita, and trapiche emerald; cross-reference to colombia.yaml.
- [Zambian Emerald](https://gemmology.dev/learn/origin/zambia): Zambian emerald characteristics, inclusions, comparison with Colombian, and market position.
- [Argyle Diamonds](https://gemmology.dev/learn/origin/australia/argyle-diamonds): The historic Argyle mine - world's primary pink diamond source, closure in 2020, and impact on the diamond market.
- [Paraiba-Type Tourmaline](https://gemmology.dev/learn/origin/east-africa/paraiba-type): Mozambican copper-bearing tourmaline with neon blue-green colours - discovery, characteristics, and the origin terminology debate.
- [Brazil – Imperial Topaz and Emerald Sub-distinctions](https://gemmology.dev/learn/origin/brazil-additional): Ouro Preto imperial topaz (Cr-coloured, strong LWUV fluorescence); Itabira vs Carnaíba emerald distinction (Cr vs V dominant, inclusion differences). Cross-reference brazil/ folder.
- [Cambodia – Pailin Sapphire and Battambang Ruby](https://gemmology.dev/learn/origin/cambodia): Cambodian gem deposits from Pailin (basaltic sapphire and ruby) and Battambang (marble-hosted ruby); Khmer Rouge era hiatus; distinction from Thai material.
- [Vietnam – Luc Yen Ruby and Cobalt-Blue Spinel](https://gemmology.dev/learn/origin/vietnam): Marble-hosted ruby and spinel from Luc Yen (Yen Bai) and Quy Chau; low-Fe high-Cr chemistry, cobalt-blue spinel, distinction from Burmese material.
- [Tajikistan – Kuh-i-Lal Spinel (Balas Ruby)](https://gemmology.dev/learn/origin/tajikistan): Kuh-i-Lal Gorno-Badakhshan red and pink spinel – historic "Balas ruby" of the Persian courts; Cr-coloured marble-hosted; trace element distinction from Mogok and Luc Yen.
- [India – Alexandrite, Diamond (Panna), and Garnet](https://gemmology.dev/learn/origin/india): Indian gem deposits – Andhra Pradesh alexandrite and chrysoberyl, Panna kimberlite diamond, Orissa garnet; geological context; Koh-i-Noor attribution qualified.
- [Iran – Nishapur (Neyshabur) Turquoise](https://gemmology.dev/learn/origin/iran): Persian turquoise from Neyshabur, Khorasan – the global colour standard; volcanic tuff host, spider-web matrix, Cu-Al phosphate, treatment assessment.
- [Mozambique – Montepuez Ruby and Paraíba Tourmaline](https://gemmology.dev/learn/origin/mozambique): Montepuez ruby (Cabo Delgado) – two-type amphibolite-hosted and alluvial; Mavuco Paraíba-type Cu-bearing tourmaline; LA-ICP-MS origin discrimination.
- [Zimbabwe – Sandawana Emerald and Marange Diamond](https://gemmology.dev/learn/origin/zimbabwe): Sandawana (Belingwe) emerald – vivid Cr-rich, tremolite inclusions, very small; Marange alluvial diamond; Murehwa chrysoberyl [CITATION NEEDED].
- [Ethiopia – Wollo Opal and Shakiso Emerald](https://gemmology.dev/learn/origin/ethiopia): Wollo (Welo) hydrophane opal – volcanic host, water-absorbing, distinct from Australian; Shakiso mica-schist emerald; Tigray sapphire [CITATION NEEDED].

### Market
- [Laboratory Reports](https://gemmology.dev/learn/market/lab-reports): Understanding gem laboratory reports from GIA, Gübelin, SSEF, GRS, and other major labs with terminology, grading, and certification.
- [Treatment Disclosure & Ethics](https://gemmology.dev/learn/market/disclosure): Treatment disclosure requirements, ethical standards, trade practices, and consumer protection in the gemstone industry.
- [Grading and Valuation](https://gemmology.dev/learn/market/grading-valuation): Colour grading (hue, tone, saturation), clarity assessment, cut quality, carat weight, and value factors for coloured gemstones.
- [Professional Practice](https://gemmology.dev/learn/market/professional-practice): Report writing, disclosure requirements, legal aspects, professional ethics, and laboratory certification for gemmologists.

### Care
- [Gem Care and Durability](https://gemmology.dev/learn/care/gem-care-durability): Gemstone stability, cleaning methods, setting recommendations, storage guidelines, and jewellery suitability for different gem species.

## Minerals

- https://gemmology.dev/minerals/actinolite
- https://gemmology.dev/minerals/actinolite-prism
- https://gemmology.dev/minerals/alexandrite
- https://gemmology.dev/minerals/almandine
- https://gemmology.dev/minerals/almandine-combination
- https://gemmology.dev/minerals/almandine-dodecahedron
- https://gemmology.dev/minerals/amazonite
- https://gemmology.dev/minerals/ambroid
- https://gemmology.dev/minerals/amethyst
- https://gemmology.dev/minerals/ametrine
- https://gemmology.dev/minerals/andalusite
- https://gemmology.dev/minerals/andalusite-chiastolite
- https://gemmology.dev/minerals/andesine
- https://gemmology.dev/minerals/andesine-tabular
- https://gemmology.dev/minerals/andradite
- https://gemmology.dev/minerals/andradite-dodecahedron
- https://gemmology.dev/minerals/apatite
- https://gemmology.dev/minerals/aquamarine
- https://gemmology.dev/minerals/aragonite
- https://gemmology.dev/minerals/augite
- https://gemmology.dev/minerals/augite-prism
- https://gemmology.dev/minerals/azurite
- https://gemmology.dev/minerals/barite
- https://gemmology.dev/minerals/benitoite
- https://gemmology.dev/minerals/beryl
- https://gemmology.dev/minerals/beryl-prism
- https://gemmology.dev/minerals/beryl-tabular
- https://gemmology.dev/minerals/bone
- https://gemmology.dev/minerals/bronzite
- https://gemmology.dev/minerals/bronzite-bronzite
- https://gemmology.dev/minerals/bronzite-cats-eye-enstatite
- https://gemmology.dev/minerals/bytownite
- https://gemmology.dev/minerals/bytownite-tabular
- https://gemmology.dev/minerals/calcite
- https://gemmology.dev/minerals/calcite-nailhead
- https://gemmology.dev/minerals/calcite-rhomb
- https://gemmology.dev/minerals/calcite-scalenohedron
- https://gemmology.dev/minerals/calcite-stacked
- https://gemmology.dev/minerals/cassiterite
- https://gemmology.dev/minerals/celestine
- https://gemmology.dev/minerals/chalcedony
- https://gemmology.dev/minerals/chalcedony-botryoidal
- https://gemmology.dev/minerals/chalcedony-massive
- https://gemmology.dev/minerals/chrome-diopside
- https://gemmology.dev/minerals/chrysoberyl
- https://gemmology.dev/minerals/chrysoberyl-cats-eye
- https://gemmology.dev/minerals/chrysoberyl-tabular
- https://gemmology.dev/minerals/chrysoberyl-trilling
- https://gemmology.dev/minerals/chrysocolla
- https://gemmology.dev/minerals/citrine
- https://gemmology.dev/minerals/colour-change-garnet
- https://gemmology.dev/minerals/colour-change-garnet-combination
- https://gemmology.dev/minerals/copal
- https://gemmology.dev/minerals/coral
- https://gemmology.dev/minerals/corundum
- https://gemmology.dev/minerals/corundum-barrel
- https://gemmology.dev/minerals/corundum-bipyramid
- https://gemmology.dev/minerals/crocoite
- https://gemmology.dev/minerals/cubic-zirconia
- https://gemmology.dev/minerals/cubic-zirconia-brilliant
- https://gemmology.dev/minerals/cuprite
- https://gemmology.dev/minerals/demantoid
- https://gemmology.dev/minerals/diamond
- https://gemmology.dev/minerals/diamond-cube
- https://gemmology.dev/minerals/diamond-macle
- https://gemmology.dev/minerals/diamond-nested-phantom
- https://gemmology.dev/minerals/diamond-octahedron
- https://gemmology.dev/minerals/diamond-phantom
- https://gemmology.dev/minerals/diopside
- https://gemmology.dev/minerals/dravite
- https://gemmology.dev/minerals/dravite-prism
- https://gemmology.dev/minerals/dyed-howlite
- https://gemmology.dev/minerals/dyed-howlite-dyed
- https://gemmology.dev/minerals/dyed-magnesite
- https://gemmology.dev/minerals/dyed-magnesite-dyed
- https://gemmology.dev/minerals/elbaite
- https://gemmology.dev/minerals/elbaite-prism
- https://gemmology.dev/minerals/emerald
- https://gemmology.dev/minerals/enstatite
- https://gemmology.dev/minerals/enstatite-prism
- https://gemmology.dev/minerals/epidote
- https://gemmology.dev/minerals/fluorite
- https://gemmology.dev/minerals/fluorite-cluster
- https://gemmology.dev/minerals/fluorite-cube
- https://gemmology.dev/minerals/fluorite-cuboctahedron
- https://gemmology.dev/minerals/fluorite-interpenetrating
- https://gemmology.dev/minerals/fluorite-octahedron
- https://gemmology.dev/minerals/fluorite-twin
- https://gemmology.dev/minerals/french-jet
- https://gemmology.dev/minerals/galena
- https://gemmology.dev/minerals/garnet
- https://gemmology.dev/minerals/garnet-combination
- https://gemmology.dev/minerals/garnet-dodecahedron
- https://gemmology.dev/minerals/garnet-topped-doublet
- https://gemmology.dev/minerals/garnet-topped-doublet-doublet
- https://gemmology.dev/minerals/garnet-trapezohedron
- https://gemmology.dev/minerals/ggg
- https://gemmology.dev/minerals/ggg-faceted
- https://gemmology.dev/minerals/glass-simulant
- https://gemmology.dev/minerals/glass-simulant-faceted
- https://gemmology.dev/minerals/goshenite
- https://gemmology.dev/minerals/grossular
- https://gemmology.dev/minerals/grossular-trapezohedron
- https://gemmology.dev/minerals/gypsum
- https://gemmology.dev/minerals/gypsum-swallowtail
- https://gemmology.dev/minerals/gypsum-tabular
- https://gemmology.dev/minerals/halite
- https://gemmology.dev/minerals/hauyne
- https://gemmology.dev/minerals/heliodor
- https://gemmology.dev/minerals/hematite
- https://gemmology.dev/minerals/hematite-kidney-ore
- https://gemmology.dev/minerals/hematite-specularite
- https://gemmology.dev/minerals/hessonite
- https://gemmology.dev/minerals/hessonite-trapezohedron
- https://gemmology.dev/minerals/hiddenite
- https://gemmology.dev/minerals/hydrogrossular
- https://gemmology.dev/minerals/jadeite
- https://gemmology.dev/minerals/jadeite-crystal
- https://gemmology.dev/minerals/jadeite-massive
- https://gemmology.dev/minerals/jet
- https://gemmology.dev/minerals/kornerupine
- https://gemmology.dev/minerals/kornerupine-cats-eye
- https://gemmology.dev/minerals/kunzite
- https://gemmology.dev/minerals/kyanite
- https://gemmology.dev/minerals/labradorite
- https://gemmology.dev/minerals/lazurite
- https://gemmology.dev/minerals/lazurite-crystal
- https://gemmology.dev/minerals/lazurite-massive
- https://gemmology.dev/minerals/luag
- https://gemmology.dev/minerals/luag-faceted
- https://gemmology.dev/minerals/magnetite
- https://gemmology.dev/minerals/malachite
- https://gemmology.dev/minerals/malachite-crystal
- https://gemmology.dev/minerals/malachite-massive
- https://gemmology.dev/minerals/maw-sit-sit
- https://gemmology.dev/minerals/maxixe-beryl
- https://gemmology.dev/minerals/moissanite
- https://gemmology.dev/minerals/moissanite-faceted
- https://gemmology.dev/minerals/moldavite
- https://gemmology.dev/minerals/moldavite-natural
- https://gemmology.dev/minerals/moonstone
- https://gemmology.dev/minerals/morganite
- https://gemmology.dev/minerals/musgravite
- https://gemmology.dev/minerals/nephrite
- https://gemmology.dev/minerals/nephrite-massive
- https://gemmology.dev/minerals/obsidian
- https://gemmology.dev/minerals/obsidian-snowflake
- https://gemmology.dev/minerals/opal
- https://gemmology.dev/minerals/opal-doublet
- https://gemmology.dev/minerals/opal-doublet-cabochon
- https://gemmology.dev/minerals/opal-triplet
- https://gemmology.dev/minerals/opal-triplet-cabochon
- https://gemmology.dev/minerals/orpiment
- https://gemmology.dev/minerals/orthoclase
- https://gemmology.dev/minerals/orthoclase-baveno
- https://gemmology.dev/minerals/orthoclase-carlsbad
- https://gemmology.dev/minerals/orthoclase-prismatic
- https://gemmology.dev/minerals/padparadscha
- https://gemmology.dev/minerals/padparadscha-bipyramid
- https://gemmology.dev/minerals/pearl
- https://gemmology.dev/minerals/pearl-aragonite
- https://gemmology.dev/minerals/pearl-nacre
- https://gemmology.dev/minerals/peridot
- https://gemmology.dev/minerals/pink-sapphire
- https://gemmology.dev/minerals/pink-sapphire-bipyramid
- https://gemmology.dev/minerals/plagioclase-albite
- https://gemmology.dev/minerals/pyrite
- https://gemmology.dev/minerals/pyrite-cluster
- https://gemmology.dev/minerals/pyrite-cube
- https://gemmology.dev/minerals/pyrite-iron-cross
- https://gemmology.dev/minerals/pyrite-pyritohedron
- https://gemmology.dev/minerals/pyrope
- https://gemmology.dev/minerals/pyrope-dodecahedron
- https://gemmology.dev/minerals/quartz
- https://gemmology.dev/minerals/quartz-amethyst-geode
- https://gemmology.dev/minerals/quartz-brazil-twin
- https://gemmology.dev/minerals/quartz-cluster
- https://gemmology.dev/minerals/quartz-dauphine-twin
- https://gemmology.dev/minerals/quartz-faden
- https://gemmology.dev/minerals/quartz-japan-twin
- https://gemmology.dev/minerals/quartz-phantom
- https://gemmology.dev/minerals/quartz-prism
- https://gemmology.dev/minerals/quartz-scepter
- https://gemmology.dev/minerals/quartz-short
- https://gemmology.dev/minerals/realgar
- https://gemmology.dev/minerals/reconstructed-turquoise
- https://gemmology.dev/minerals/red-beryl
- https://gemmology.dev/minerals/rhodochrosite
- https://gemmology.dev/minerals/rhodochrosite-banded
- https://gemmology.dev/minerals/rhodolite
- https://gemmology.dev/minerals/rhodonite
- https://gemmology.dev/minerals/rose-quartz
- https://gemmology.dev/minerals/rose-quartz-massive
- https://gemmology.dev/minerals/rose-quartz-star
- https://gemmology.dev/minerals/ruby
- https://gemmology.dev/minerals/ruby-star
- https://gemmology.dev/minerals/rutile
- https://gemmology.dev/minerals/sanidine
- https://gemmology.dev/minerals/sanidine-tabular
- https://gemmology.dev/minerals/sapphire
- https://gemmology.dev/minerals/sapphire-star
- https://gemmology.dev/minerals/scapolite
- https://gemmology.dev/minerals/scapolite-cats-eye
- https://gemmology.dev/minerals/scapolite-prismatic
- https://gemmology.dev/minerals/scheelite
- https://gemmology.dev/minerals/schorl
- https://gemmology.dev/minerals/schorl-prism
- https://gemmology.dev/minerals/serpentine
- https://gemmology.dev/minerals/serpentine-bowenite
- https://gemmology.dev/minerals/serpentine-williamsite
- https://gemmology.dev/minerals/sinhalite
- https://gemmology.dev/minerals/slocum-stone
- https://gemmology.dev/minerals/smoky-quartz
- https://gemmology.dev/minerals/smoky-quartz-morion
- https://gemmology.dev/minerals/smoky-quartz-prism
- https://gemmology.dev/minerals/sodalite
- https://gemmology.dev/minerals/sodalite-crystal
- https://gemmology.dev/minerals/sodalite-massive
- https://gemmology.dev/minerals/soude-emerald
- https://gemmology.dev/minerals/soude-emerald-doublet
- https://gemmology.dev/minerals/spessartine
- https://gemmology.dev/minerals/sphene
- https://gemmology.dev/minerals/spinel
- https://gemmology.dev/minerals/spinel-macle
- https://gemmology.dev/minerals/spinel-octahedron
- https://gemmology.dev/minerals/spodumene
- https://gemmology.dev/minerals/spodumene-prism
- https://gemmology.dev/minerals/star-diopside
- https://gemmology.dev/minerals/star-diopside-star-cabochon
- https://gemmology.dev/minerals/staurolite
- https://gemmology.dev/minerals/staurolite-cross-60
- https://gemmology.dev/minerals/staurolite-cross-90
- https://gemmology.dev/minerals/strontium-titanate
- https://gemmology.dev/minerals/strontium-titanate-faceted
- https://gemmology.dev/minerals/sunstone
- https://gemmology.dev/minerals/synthetic-alexandrite-czochralski
- https://gemmology.dev/minerals/synthetic-alexandrite-czochralski-boule
- https://gemmology.dev/minerals/synthetic-alexandrite-flux
- https://gemmology.dev/minerals/synthetic-alexandrite-flux-crystal
- https://gemmology.dev/minerals/synthetic-alexandrite-hydrothermal
- https://gemmology.dev/minerals/synthetic-alexandrite-hydrothermal-crystal
- https://gemmology.dev/minerals/synthetic-coral
- https://gemmology.dev/minerals/synthetic-coral-cabochon
- https://gemmology.dev/minerals/synthetic-diamond-cvd
- https://gemmology.dev/minerals/synthetic-diamond-cvd-plate
- https://gemmology.dev/minerals/synthetic-diamond-hpht
- https://gemmology.dev/minerals/synthetic-diamond-hpht-cuboctahedron
- https://gemmology.dev/minerals/synthetic-emerald-flux
- https://gemmology.dev/minerals/synthetic-emerald-flux-crystal
- https://gemmology.dev/minerals/synthetic-emerald-hydrothermal
- https://gemmology.dev/minerals/synthetic-emerald-hydrothermal-crystal
- https://gemmology.dev/minerals/synthetic-emerald-lechleitner
- https://gemmology.dev/minerals/synthetic-emerald-lechleitner-crystal
- https://gemmology.dev/minerals/synthetic-lapis-gilson
- https://gemmology.dev/minerals/synthetic-lapis-gilson-cabochon
- https://gemmology.dev/minerals/synthetic-opal-gilson
- https://gemmology.dev/minerals/synthetic-opal-gilson-cabochon
- https://gemmology.dev/minerals/synthetic-paraiba
- https://gemmology.dev/minerals/synthetic-paraiba-crystal
- https://gemmology.dev/minerals/synthetic-quartz-hydrothermal
- https://gemmology.dev/minerals/synthetic-quartz-hydrothermal-crystal
- https://gemmology.dev/minerals/synthetic-ruby-flux
- https://gemmology.dev/minerals/synthetic-ruby-flux-crystal
- https://gemmology.dev/minerals/synthetic-ruby-hydrothermal
- https://gemmology.dev/minerals/synthetic-ruby-hydrothermal-crystal
- https://gemmology.dev/minerals/synthetic-ruby-kashan-flux
- https://gemmology.dev/minerals/synthetic-ruby-kashan-flux-crystal
- https://gemmology.dev/minerals/synthetic-ruby-verneuil
- https://gemmology.dev/minerals/synthetic-ruby-verneuil-boule
- https://gemmology.dev/minerals/synthetic-rutile
- https://gemmology.dev/minerals/synthetic-rutile-faceted
- https://gemmology.dev/minerals/synthetic-sapphire-czochralski
- https://gemmology.dev/minerals/synthetic-sapphire-czochralski-crystal
- https://gemmology.dev/minerals/synthetic-sapphire-flux
- https://gemmology.dev/minerals/synthetic-sapphire-flux-crystal
- https://gemmology.dev/minerals/synthetic-sapphire-verneuil
- https://gemmology.dev/minerals/synthetic-sapphire-verneuil-boule
- https://gemmology.dev/minerals/synthetic-spinel-verneuil
- https://gemmology.dev/minerals/synthetic-spinel-verneuil-boule
- https://gemmology.dev/minerals/synthetic-turquoise-gilson
- https://gemmology.dev/minerals/synthetic-turquoise-gilson-cabochon
- https://gemmology.dev/minerals/taaffeite
- https://gemmology.dev/minerals/tanzanite
- https://gemmology.dev/minerals/topaz
- https://gemmology.dev/minerals/topaz-prism
- https://gemmology.dev/minerals/topaz-tabular
- https://gemmology.dev/minerals/tourmaline
- https://gemmology.dev/minerals/tourmaline-prism
- https://gemmology.dev/minerals/tourmaline-watermelon
- https://gemmology.dev/minerals/tremolite
- https://gemmology.dev/minerals/tremolite-prism
- https://gemmology.dev/minerals/tsavorite
- https://gemmology.dev/minerals/turquoise
- https://gemmology.dev/minerals/turquoise-crystal
- https://gemmology.dev/minerals/turquoise-massive
- https://gemmology.dev/minerals/uvarovite
- https://gemmology.dev/minerals/uvarovite-druse
- https://gemmology.dev/minerals/vesuvianite
- https://gemmology.dev/minerals/vulcanite
- https://gemmology.dev/minerals/wulfenite
- https://gemmology.dev/minerals/yag
- https://gemmology.dev/minerals/yag-faceted
- https://gemmology.dev/minerals/zircon

## Licensing
- Code: MIT
- Educational content: CC BY-SA 4.0

## Source
- https://github.com/gemmology-dev