Gem Care and Durability

Introduction

Understanding gemstone durability is essential for recommending appropriate settings,
cleaning methods, and care instructions. Durability encompasses three factors:
hardness, toughness, and stability.

A gem suitable for everyday ring wear must score well in all three areas. Many
beautiful gems are better suited for occasional wear or protected settings.

The Three Durability Factors

Hardness

Resistance to scratching
Measured on Mohs scale (1-10)
Important for wear resistance
Gems below 7 scratch easily
Dust contains quartz (H 7)

Toughness

Resistance to breaking/chipping
Related to crystal structure
Cleavage reduces toughness
Jade is tougher than diamond
Important for impact resistance

Stability

Resistance to chemicals/light/heat
Fading from light exposure
Damage from heat or acids
Some gems are temperature sensitive
Important for long-term care

Hardness Considerations

The Mohs scale is ordinal, not linear—the jump from 9 to 10 is enormous. Household
dust contains quartz particles (H 7), so gems below 7 will gradually accumulate
scratches during normal wear.

Hardness Categories for Jewellery

Category	Hardness	Suitability	Examples
Excellent	8-10	Daily ring wear	Diamond, ruby, sapphire, chrysoberyl
Good	7-7.5	Everyday with care	Quartz, tourmaline, garnet, beryl
Fair	6-7	Occasional wear; protective settings	Peridot, tanzanite, moonstone
Poor	5-6	Earrings/pendants; very careful ring	Opal, turquoise, apatite
Fragile	<5	Display or very protected wear	Pearl, coral, amber, fluorite

Toughness and Cleavage

Cleavage—the tendency to break along crystallographic planes—significantly affects
toughness. Even hard gems can be brittle.

High-Risk Cleavage Gems

Gem	Cleavage	Risk
Diamond	Perfect octahedral {111}	Can cleave with sharp blow
Topaz	Perfect basal {001}	Very prone to chipping
Kunzite	Perfect prismatic	Extremely fragile for setting
Fluorite	Perfect octahedral {111}	Very brittle
Tanzanite	Perfect {010}	Easily damaged in setting
Feldspar (moonstone)	Perfect two directions	Prone to chipping

Tough Gems

Some gems have exceptional toughness despite moderate hardness:

Nephrite jade (H 6-6.5): Interlocking fibrous structure
Jadeite (H 6.5-7): Granular interlocking structure
Chalcedony (H 7): Microcrystalline aggregate

These gems resist chipping better than single-crystal gems of higher hardness.

Stability Factors

Many gems are sensitive to environmental conditions that can cause fading,
colour change, or physical damage.

Light Sensitivity

Gem	Risk	Notes
Kunzite	High	Fades significantly; store in dark
Amethyst	Moderate	Can fade with prolonged exposure
Rose quartz	Low to moderate	May fade slightly
Brown topaz	High	Natural brown fades; irradiated stable
Chrysoprase	Moderate	Can fade and dry out
Turquoise	Moderate	Can fade and dehydrate

Heat Sensitivity

Gem	Risk	Damage Type
Opal	Very high	Crazing from dehydration
Pearl	High	Nacre damage, peeling
Emerald (oiled)	High	Oil can exude
Tanzanite	High	Colour may change; cleavage risk
Tourmaline	Moderate	Some colours may change
Kunzite	High	Can lose colour

Chemical Sensitivity

Gem	Sensitive To	Effect
Pearl	Acids, perfume, hairspray	Nacre dissolution
Coral	Acids	Surface etching
Turquoise	Oils, cosmetics	Discolouration
Malachite	Acids	Surface damage
Lapis lazuli	Acids	Pyrite tarnish, surface damage
Amber	Solvents, alcohol	Surface damage

Cleaning Methods

Different gems require different cleaning approaches. Using the wrong method can
cause permanent damage.

Safe Cleaning Methods

Method	Description	Safe For	Never Use For
Warm soapy water	Mild dish soap, soft brush	Most gems	Porous gems (turquoise)
Ultrasonic	Sound waves agitate cleaning solution	Diamond, ruby, sapphire (untreated)	Emerald, tanzanite, opal, pearl
Steam	High-pressure steam jet	Diamond, ruby, sapphire (untreated)	Filled gems, porous gems, soft gems
Dry brush	Soft brush, no liquid	Porous gems	N/A (gentle method)

Ultrasonic Cleaning Safety

Ultrasonic cleaners use vibration to remove dirt but can cause damage to:

Filled gems: Can remove or damage fillers (emerald, ruby)
Gems with cleavage: Vibration can propagate fractures
Fragile inclusions: Can cause expansion/damage
Organic gems: Can damage pearl nacre, amber
Treated gems: May affect surface treatments

Steam Cleaning Safety

Steam cleaning combines heat and moisture, dangerous for:

Oiled emeralds: Heat can remove oil
Heat-sensitive gems: Thermal shock risk
Filled gems: Heat damages many fillers
Opal: Rapid temperature change causes crazing

Cleaning Safety Chart

Cleaning Method Safety by Gem

Gem	Warm Soapy Water	Ultrasonic	Steam
Diamond (natural)	Safe	Usually safe	Usually safe
Ruby/Sapphire (untreated)	Safe	Usually safe	Usually safe
Ruby/Sapphire (heated)	Safe	Caution	Caution
Emerald (oiled)	Safe	Never	Never
Aquamarine	Safe	Usually safe	Usually safe
Tanzanite	Safe	Never	Never
Tourmaline	Safe	Caution	Caution
Opal	Caution	Never	Never
Pearl	Safe (brief)	Never	Never
Turquoise	Never (dry brush)	Never	Never

Setting Recommendations

The choice of setting can protect vulnerable gems or expose durable gems to show
their beauty.

Protective Settings

Setting Type	Protection Level	Best For
Bezel	High	Soft gems, cleavage-prone gems
Half-bezel	Moderate	Balance of protection and light
Flush/gypsy	Very high	Rings for active wearers
Halo	Moderate	Central stone protected by smaller stones

Exposed Settings

Setting Type	Protection Level	Requires
Prong/claw	Low	Hardness 7+ for rings
Tension	Low	Very hard, tough gems only
Bar	Low to moderate	Harder gems preferred

Setting by Gem Type

Recommended for prong settings (rings):
Diamond, ruby, sapphire, chrysoberyl, spinel

Recommend bezel or protective settings:
Emerald, tanzanite, opal, moonstone, tourmaline, peridot

Best avoided in rings:
Kunzite, fluorite, apatite, pearl (unless protective setting)

Storage Guidelines

Separation

Store gems separately to prevent harder gems from scratching softer ones:

Individual pouches or compartments
Soft fabric lining
Never loose in a box together
Diamond will scratch everything else

Environment

Humidity: Some gems need moisture (opal, pearl); others need dry (iron pyrite)
Light: Store light-sensitive gems in dark containers
Temperature: Avoid extreme temperatures; room temperature ideal
Air: Some gems need ventilation; airtight can trap moisture

Special Storage Needs

Gem	Special Requirements
Opal	Damp cotton nearby; avoid airtight; stable temperature
Pearl	Breathable container; occasional wear maintains moisture
Amber	Away from solvents and heat
Kunzite	Complete darkness
Turquoise	Away from oils and cosmetics

Jewellery Suitability Chart

Gem Suitability by Jewellery Type

Gem	Daily Ring	Occasional Ring	Earrings	Pendant	Bracelet
Diamond	Excellent	Excellent	Excellent	Excellent	Excellent
Ruby/Sapphire	Excellent	Excellent	Excellent	Excellent	Excellent
Emerald	Caution	Good	Excellent	Excellent	Caution
Aquamarine	Good	Excellent	Excellent	Excellent	Good
Tanzanite	Poor	Caution	Good	Good	Poor
Tourmaline	Good	Excellent	Excellent	Excellent	Good
Opal	Poor	Caution	Good	Good	Poor
Pearl	Caution	Good	Excellent	Excellent	Caution
Moonstone	Caution	Good	Excellent	Excellent	Caution
Peridot	Caution	Good	Good	Good	Caution
Kunzite	Poor	Poor	Good	Good	Poor
Topaz	Good	Excellent	Excellent	Excellent	Good

Special Care Gems

Opal

Opal contains 3-21% water and is prone to "crazing" (network of fine cracks):

Avoid rapid temperature changes
Store with damp cotton (not wet)
Never use ultrasonic or steam
Keep away from direct sunlight and heat
Doublets and triplets are especially vulnerable to water

Pearl

Pearls are sensitive to acids, cosmetics, and drying:

Apply perfume and hairspray before putting on pearls
Wipe with soft cloth after wearing
Store in breathable fabric, not plastic
Restring regularly (silk stretches and weakens)
Occasional wearing maintains moisture balance

Emerald

Nearly all emeralds are oiled to improve apparent clarity:

Oil can dry out or exude over time
Avoid ultrasonic and steam cleaning
Avoid heat (jeweller's torch is dangerous)
May need periodic re-oiling
Store away from heat sources

Tanzanite

Tanzanite has perfect cleavage and is heat-sensitive:

Extremely vulnerable during setting (cleavage)
Never use ultrasonic or steam
Avoid sudden temperature changes
Not recommended for daily ring wear
Excellent for earrings and pendants