Prehnite
Last updated: April 2026
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).
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
Key Differentiators
- Pale apple-green to yellow-green color typical
- RI 1.611–1.665 — lower than jadeite (1.654–1.688)
- SG 2.82–2.94 — much lower than jadeite (3.25–3.40)
- Often shows fibrous internal texture under 10x loupe
- Frequently associated with epidote inclusions (yellowish-green crystals)
Common Simulants
- Jadeite jade: Jadeite: RI 1.666; SG 3.34; higher luster; more uniform color; harder (6.5–7 Mohs).
- Nephrite jade: Nephrite: aggregate fibrous; SG 2.90–3.02; tougher; RI 1.600–1.627.
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.
Measurement Guides
Identifying a prehnite? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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