Orthoclase
Chemical Formula	KAlSi3O8
Species	Silicates
Crystal System	Monoclinic
Mohs Scale	6
Specific Gravity	2.55-2.63
Color	Colorless, Greenish, Grayish yellow, White, Pink
Streak	white
Luster	Vitreous
Refractive Index	n = 1.518 - 1.520 n = 1.522 - 1.524 n = 1.522 - 1.525
Diaphaneity	Transparent, Translucent
Cleavage	PerfectPerfect on , good on
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Can be anhedral or euhedral. Grains are commonly elongate with a tabular appearance.
Geological Setting：Common feldspar of granites, syenites and high grade metamorphic rocks.