Cause of Color :
Iron (increasing iron content changes into hypersthene)
Chemical Composition :
Silicate of Magnesium and Iron – (Mg,Fe)SiO3. Increasing iron content changes into Hypersthene.
Classification / Type :
Enstatite belongs to the orthopyroxene group. Of gem interest are enstatite, bronzite, hypersthene (increasing iron content) and the intermediate series. As a result there is a variation in properties, with higher values for stones with higher iron content.
Crystal System / Forms :
Orthorhombic System / Prismatic crystals; twinning is common.
Cuts & Uses :
Facetted cuts, cabochons, beads, etc.
5 - 6 (Enstatite - Hypersthene)
Parting planes and cleavage cracks, liquid fingerprints and crystal inclusions.
Optic Character :
- Enstatite: Biaxial positive
- Hypersthene: Biaxial negative
Moderate: green / yellowish green / brownish green
Refractive Index / Birefringence :
- Enstatite: 1.663 – 1.673 / 0.010
- Hypersthene: 1.673 – 1.683 and 1.715 – 1.731
Simulants (with separation tests) :
Diopside (R.I., birefringence), Kornerupine (spectrum, pleochroism), Sillimanite (R.I., birefringence, spectrum), Moldavite (optic character).
Myanmar, Sri Lanka, India, South Africa, Tanzania, U.S.A., Norway, Greenland.
Strong lines at 505nm, 550nm, 483nm, 459nm, 449nm, 425nm.