1.
What is Feldspar?
The
feldspars (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8 – BaAl2Si2O8) are a group of frame-like
structure anhydrous aluminosilicate minerals, which are the most common mineral
in the Earth, making up as much as 60% of the Earth's crust.
Generally
speaking, there are three categories of feldspar: orthoclase (K-feldspar), plagioclase
and celsian. Feldspar has two directions of cleavage that meet at close to a 90
degree angle. The included angle between two sets of cleavages of orthoclase is
equal to 90 degrees, and less than 90 degrees for plagioclase.
