Tephroite Value, Price, and Jewelry Information


Tephroite
Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Tephroite is generally reddish brown and barely translucent. However, it takes a good polish and is massive enough to make good cabochons. Only the New Jersey and Australian localities seem to have provided such material, however. Faceted gems are unknown.

Tephroite Value

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Tephroite Information

DataValue
NameTephroite
Is a Variety ofPeridot (Olivine, Chrysolite)
Crystallography Orthorhombic; crystals prismatic, elongated: commonly massive, compact. as disseminated grains.
Colors Reddish brown, salmony pink, blue-green, olive, green, gray.
Luster Vitreous to greasy.
Fracture Conchoidal, uneven; brittle.
Hardness 6.
Specific Gravity 4.11.
Birefringence 0.037 - 0.047.
Cleavage Distinct.
Spectral Not reported, but Mn lines should be observed.
FormulaMn2SiO4.
Pleochroism Distinct: greenish blue/reddish/brownish red.

Streak: pale gray.

Optics: a =1.770-1.788; β= 1.807-1.810; γ=1.817-1.825.

Biaxial (—).

Occurrence: In iron-manganese ore deposits and associated skarns.

California; Colorado.

Franklin and Sterling Hill, New Jersey: cuttable.

England; Sweden; France; Japan.

Tamworth. NS.W. Australia: small Mn deposits with massive tephroite streaks in rhodonite.

This material is suitable for cabochons.

Comments: Tephroite is generally reddish brown and barely translucent. However, it takes a good polish and is massive enough to make good cabochons. Only the New Jersey and Australian localities seem to have provided such material, however. Faceted gems are unknown.

Name: From the Greek tephros, meaning ash colored.