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Diameter, mm (1mm - 0,039inch)

Stone sphere balls - full range in stock "Staurolite"

Staurolite is a mineral whose name comes from the Greek cross and stone. Single crystals of staurolite in the form of "sleepers" often form crosses among themselves. Oblique crosses are common. Straight crosses are much rarer. In Basel (Switzerland) straight splices of staurolite were used for baptism. Therefore, it is also called the Basel baptismal stone. The best samples of staurolite in the world are mined in Russia, in Keivy on the Kola Peninsula.

You can see staurolite stone for sale and buy it in the Minerals of Russia online store. 

Physical Properties of Staurolite

General
Category Nesosilicate
Formula
(repeating unit)
Fe2+2Al9O6(SiO4)4(O,OH)2
IMA symbol St
Strunz classification 9.AF.30
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group C2/m
Unit cell a = 7.86 Å, b = 16.6 Å
c = 5.65 Å; β = 90.45°; Z = 2
Identification
Color Dark reddish brown to blackish brown, yellowish brown, rarely blue; pale golden yellow in thin section
Crystal habit Commonly in prismatic crystals
Twinning Commonly as 60° twins, less common as 90° cruciform twins
Cleavage Distinct on {010}
Fracture Subconchoidal
Tenacity Brittle
Mohs scale hardness 7 - 7.5
Luster Subvitreous to resinous
Streak White to grayish
Diaphaneity Transparent to opaque
Specific gravity 3.74 - 3.83 meas. 3.686 calc.
Optical properties Biaxial (+)
Refractive index nα = 1.736 - 1.747 nβ = 1.740 - 1.754 nγ = 1.745 - 1.762
Birefringence δ = 0.009 - 0.015
Pleochroism X = colorless; Y = pale yellow; Z = golden yellow
2V angle Measured: 88°, Calculated: 84° to 88°
Dispersion r > v; weak
Code: 2540
Keivy, Kola Peninsula, RF
54mm

0.00 $ $296.36

Code: 1384
Keivy, Kola Peninsula, RF
57mm

0.00 $ $349.09

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