Physical & Optical Properties

RI Range1.611–1.665
SG Range2.82–2.94
SG Typical2.88
Hardness (Mohs)6–6.5
Crystal SystemOrthorhombic
Optic CharacterDR Biaxial (+)
Birefringence0.030
Dispersion0.020
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismNone
ColorsGreen, Yellow Orange, Colorless
SpeciesPrehnite
GreenYellow OrangeColorless

Key Differentiators

Common Simulants

Commonly Confused With

Commonly confused with: Jadeite, Nephrite, Peridot.

Price Context

Natural — low ($/ct)$5
Natural — high ($/ct)$100
NotePer carat; widely available cabochon material

Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.

About Prehnite

Pale apple-green prehnite is common in estate jewelry as cabochons and beads, often confused with jade or green glass. Lower RI (1.611–1.665) and SG separate it from jadeite; fibrous internal texture is often visible under loupe. Frequently intergrown with epidote (yellowish-green crystals).

Identifying a prehnite? GemID walks through these tests in order — RI, SG, fluorescence, and more.

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