Microcline (Silicate-Tectosilicate)
KAlSi3O8Hardness: 6.0
Specific Gravity: 2.56
Characteristics: Potassium feldspar; very common mineral; white, bluish-green, or salmon pink; perfect cleavage in one direction and good in another; vitreous luster; usually translucent; prismatic crystals; insoluble in HCl and nitric acids.
Found in granitic intrusives, syenites, arkosic sandstones and conglomerates, and gneisses.
A principle use of microcline is in the manufacture of porcelain and sometimes to supply alumina in the manufacture of glass.
(Primary text: Perkins, D. 2002. Mineralogy. Prentice Hall.)