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

Orthoclase mineral - You can buy these samples

Orthoclase is a variety of potassium feldspar. As a rock-forming mineral, it is included in the composition of granites, syenites, and also in the composition of some gneisses and effusives. Used to make porcelain. Jewelers sometimes use faceted translucent orthoclase specimens in their pieces.

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

Physical properties of Orthoclase

Category Silicate mineral
(repeating unit)
IMA symbol Or
Strunz classification 9.FA.30
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group C2/m
Color Colorless, greenish, greyish yellow, white, pink
Crystal habit Can be anhedral or euhedral. Grains are commonly elongate with a tabular appearance.
Twinning Typically displays Carlsbad twinning. Baveno and manebach twins have also been reported in orthoclase.
Cleavage Has perfect cleavage on {001} and good cleavage on {010}. Cleavages intersect at 90°. It can be difficult to see cleavage in thin section due to orthoclase's low relief.
Fracture Uneven
Mohs scale hardness 6 (defining mineral)
Luster Vitreous, pearly on cleavage surfaces
Streak White
Diaphaneity Transparent to translucent
Specific gravity 2.55–2.63
Optical properties Biaxial (-), 2V = 65–75
Refractive index nα = 1.518–1.520
nβ = 1.522–1.524
nγ = 1.522–1.525
Birefringence 0.0050–0.0060
Dispersion Relatively strong
Extinction Parallel to cleavage
Length fast/slow No slow or fast length
Diagnostic features Distinguishable from microcline by a lack in gridiron twinning. Distinguishable from sanidine by a larger 2Vx.
Other characteristics Low negative relief;
Alters to sericite or clay (commonly)
Code: 1755
Manifestation "Luck", Khabarovsk Territory, Primorye, RF

0.00 $ $51.67

Code: 2048
Manifestation "Luck", Khabarovsk Territory, Primorye, RF

0.00 $ $51.67

Code: 2401
Manifestation "Luck", Khabarovsk region, Primorye, RF

0.00 $ $54.00

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