Dioptase Value, Price, and Jewelry Information


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

Dioptase is abundant in mineral collections throughout the world and is not considered a great rarity, but faceted gems are extremely rare due to a paucity of clean fragments. Clean stones over 1 carat are virtually nonexistent, and few collections have stones at all. Cabochons are blue-green, translucent, and quite attractive but are much too soft for wear.

Dioptase Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Dioptase Information

DataValue
NameDioptase
Crystallography Hexagonal. Fine crystals are common in certain localities; stubby, elongated.
Colors Rich emerald green, bluish green.
Luster Vitreous; greasy on fractures.
Fracture Conchoidal to uneven. Brittle.
Hardness 5
Specific Gravity 3.28-3.35
Birefringence 0.053
Cleavage Perfect 1 direction.
Dispersion 0.036
Stone SizesCrystals may be fairly large, but clean areas within such crystals are always very small, and stones are never larger than 1-2 carats. Cabochons up to about 15 carats are sometimes cut from translucent masses.
Luminescence None
Spectral Broad band at about 5500; strong absorption of blue and violet.
FormulaCuSiO2(OH)2.

Dioptase Information

Streak: Pale blue-green.

Optics:  o = 1.644-1.658; e= 1.697-1.709. Uniaxial (+).

Occurrence: Oxidized zone of copper deposits. Zaire; Chile; USSR

Arizona: microscopic crystals.

Guchab and Tsumeb, Namibia: world’s finest crystals, some transparent but mostly filled with cleavage planes and fractures. These crystals are a superb color, on matrix, and up to 2 inches long.

Comments: Dioptase is abundant in mineral collections throughout the world and is not considered a great rarity, but faceted gems are extremely rare due to a paucity of clean fragments. Clean stones over 1 carat are virtually nonexistent, and few collections have stones at all. Cabochons are blue-green, translucent, and quite attractive but are much too soft for wear.

Name: From Greek words meaning to see through because the cleavage directions can be determined just by looking into the crystals.