Inderite Value, Price, and Jewelry Information

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

Inderite

Inderite is very soft and difficult to cut, and only a few stones have been cut by hobbyists. There is plenty of cuttable material in existence, and although the material comes from only a few localities, it is not considered a great rarity. The surface of cut stones may become white and cloudy after cutting; care must be taken in storage and to dry the stones after cutting.

Inderite Information

Data Value
Name Inderite
Varieties Kurnakovite
Colors Colorless; massive varieties white to pink.
Alternate Common Names Also known as Lesserite; dimorph of Kurnakovite.
Crystallography Monoclinic. Crystals prismatic, up to 10 x 1cm; nodular; acicular crystals also.
Refractive Index 1.486-1.507
Luster Vitreous; pearly on cleavage.
Hardness 2.5.
Fracture Uneven
Specific Gravity 1.78-1.86
Birefringence 0.017-0.020.
Cleavage Perfect 1 direction
Stone Sizes Gems over 50 carats or more could be cut from large transparent crystals.
Luminescence None.
Luminescence Present No
Transparency Transparent.
Absorption Spectrum Not diagnostic.
Formula

Mg2B6O11 · 15H2O.
Optics

a = 1.486-1.489; β = 1.488-1.493; γ = 1.504-1.507. Biaxial (+), 2V= 37-52°.
Optic Sign Biaxial +

Optics: a = 1.486-1.489; β = 1.488-1.493; γ = 1.504-1.507.

Biaxial (+), 2V= 37-52°.

Occurrence: Borate deposits in arid regions.

Kern County, California: large crystals, often transparent. Inder borate deposit, Kazakhstan, USSR: as nodules in red clay.

Comments: Inderite is very soft and difficult to cut, and only a few stones have been cut by hobbyists. There is plenty of cuttable material in existence, and although the material comes from only a few localities, it is not considered a great rarity. The surface of cut stones may become white and cloudy after cutting; care must be taken in storage and to dry the stones after cutting.

Name: After the locality, Inder Lake, Kazakhstan, USSR.

by Joel E. Arem, Ph.D., FGA