Sogdianite Value, Price, and Jewelry Information

Sogdianite

Sogdianite is an extremely rare mineral, suitable for cabochons. The color is striking and the material is hard enough to take a good polish. It is usually mixed with other minerals, so the SG and hardness are variable. Chemical analysis may be required to differentiate sogdianite from sugilite, but the latter is far more abundant.

Sogdianite Information

Data Value
Name Sogdianite
Colors Bright violet.
Crystallography Hexagonal; crystals not observed; massive, platy.
Refractive Index 1.606-1.608
Luster Vitreous to waxy.
Hardness 7, if pure (South Africa: 5-6).
Specific Gravity 2.90, if pure (South Africa: 2.76).
Birefringence 0.002
Cleavage Perfect 1 direction
Luminescence Very weak dark red in SW, weak violet in LW.
Luminescence Present Yes
Luminescence Type Fluorescent, UV-Long, UV-Short
Transparency Transparent to opaque.
Absorption Spectrum Diagnostic, sharp lines at 4110, 4190, and 4370; weak bands at 4880-4930 and 6300-6450.
Formula

(K,Na)2Li2(Li,Fe,Al,Ti)2Zr2(Si2O5)6.

Pleochroism

Not reported.

Optics

o = 1.606; e = 1.608. Uniaxial (-).

Optic Sign Uniaxial -

Optics: 0 = 1.606; e = 1,608,

Uniaxial (-).

Occurrence: ln the Alai Range, Tajikistan, platy masses up to 10 X 7 X 4 cm, in a vein pegmatoidal body compositionally like an alkalic granite.

Also occurs at the Wessel Mine, Karuman, North Cape Province. South Africa.

Comments: Sogdianite is an extremely rare mineral, suitable for cabochons. The color is striking and the material is hard enough to take a good polish. It is usually mixed with other minerals, so the SG and hardness are variable. Chemical analysis may be required to differentiate sogdianite from sugilite, but the latter is far more abundant.

Name: From Sogdiana, the name of an ancient state in Middle Asia.

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