Enstatite
Last updated: April 2026
Chrome enstatite is a chromium-bearing orthorhombic pyroxene producing rich green color, found primarily in Madagascar, Myanmar, and India; it is a collector's gemstone due to its low hardness, perfect cleavage, and limited availability in faceted form.
Physical & Optical Properties
RI Range1.663–1.673
SG Range3.20–3.30
SG Typical3.27
Hardness (Mohs)5–5.5
Crystal SystemOrthorhombic
Optic CharacterDR Biaxial (+)
Birefringence0.010
Dispersion0.017
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterRed
PleochroismStrong Trichroic
ColorsGreen
SpeciesEnstatite (pyroxene — MgSiO₃)
VarietyChrome Enstatite
Key Differentiators
- Chelsea filter red reaction — chromium-bearing; shared with chrome diopside but different RI/SG
- Low hardness 5–5.5 (scratched by quartz H 7 and feldspar H 6); practical cutting challenges
- Perfect cleavage in two prismatic directions at nearly 90° — risk of cleavage during cutting and wear
- Biaxial positive; RI 1.663–1.673 range is characteristic vs. chrome diopside (RI 1.664–1.695, biaxial negative)
- Strong trichroism (green / yellow-green / brown-green) distinguishes from isotropic green garnets
Common Simulants
- Chrome Diopside: Chrome diopside: biaxial negative (B-), RI 1.664–1.695 (higher upper end), SG 3.27–3.38; Chelsea red from Cr; similar green color. Optic sign and upper RI limit separate from enstatite (B+, RI max 1.673).
- Chrome Tourmaline: Tourmaline: uniaxial negative (DR), RI 1.624–1.644 (lower), strong dichroism, Chelsea red from Cr; hardness 7–7.5 (harder than enstatite); SG 2.82–3.32.
- Green Glass: Isotropic (SR), no pleochroism, gas bubbles or swirl marks under loupe; variable RI and SG depending on formulation; no cleavage planes.
Price Context
Natural — low ($/ct)$30
Natural — high ($/ct)$500
NotePer carat; common chrome enstatite $30–100/ct; fine vivid-green Madagascar chrome enstatite $100–500/ct; collector stone with limited mainstream demand due to low hardness
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
Measurement Guides
Identifying an enstatite? GemID walks through these tests in order — RI, SG, fluorescence, and more.
Try GemID Free →