orthorhombic Nesosilicates
Peridot
(Mg,Fe)2SiO4
Crystal Structure
#! Species: Peridot (Olivine)
#! System: Orthorhombic (mmm)
#! Habit: Short prismatic with lily pad inclusions
orthorhombic[mmm]:{110}@1.0[inclusion:lily_pad] + {010}@0.7 + {021}@0.5
orthorhombic
mmm
{110} {010} {021}
Quick Facts
Hardness
6.5
Specific Gravity
3.27
Refractive Index
1.654
Optical Character
Biaxial +
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Open in PlaygroundPhysical Properties
Crystal Systemorthorhombic
Hardness (Mohs)6.5
Specific Gravity3.27
CleavagePoor
FractureConchoidal
LustreVitreous to oily
Optical Properties
Refractive Index1.654
Birefringence0.035-0.038
Optical CharacterBiaxial +
Dispersion0.02
Pleochroismweak: Yellow-green / Green / Greenish-yellow (Subtle difference; may be difficult to detect)
Colours
Yellow-greenOlive greenLime greenBrownish-green
Localities
Myanmar (Mogok)Pakistan (Kashmir)China (Changbai)Arizona, USAEgypt (Zabargad)VietnamEthiopia
Common Inclusions
Lily pad inclusions (diagnostic)Chromite crystalsNeedle inclusionsNegative crystalsHealing feathers
Crystal Forms
prismpinacoiddome
Diagnostic Features
Strong doubling visible through table; distinctive yellowish-green; high birefringence (0.036)
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Open in PlaygroundRelated Minerals
Other minerals in the orthorhombic system
