Peridot
Known for its distinctive olive-green color and strong birefringence.
Physical & Optical Properties
RI Range1.654–1.690
SG Range3.27–3.48
SG Typical3.34
Hardness (Mohs)6.5–7
Crystal SystemOrthorhombic
Optic CharacterDR Biaxial (+)
Birefringence0.036
Dispersion0.020
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismWeak
ColorsGreen, Yellow Orange
SpeciesOlivine
Key Differentiators
- Very strong facet doubling
- Characteristic 'lily pad' inclusions
- Vitreous luster
Common Simulants
- Green Tourmaline: Tourmaline: uniaxial negative DR; RI 1.624–1.644; SG 3.06; less characteristic doubling than peridot.
- Demantoid Garnet: Demantoid: isotropic SR; no doubling; very high RI (1.888); higher dispersion (fire); SG 3.84.
- Green Glass: Isotropic; no facet doubling; gas bubbles under loupe; conchoidal fracture.
Commonly Confused With
Commonly confused with: Tourmaline, Demantoid Garnet, glass, Prasiolite, Prehnite, Sinhalite, Synthetic Spinel.
Treatments
- Fracture Filling (rare)
Price Context
Natural — low ($/ct)$30
Natural — high ($/ct)$200
NotePer carat; deep green with no brownish modifier; Burmese and Pakistani material command premium
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
About Peridot
Known for its distinctive olive-green color and strong birefringence.
Identifying a peridot? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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