Forms of this mineral include labradorite, albite, and microcline, and the presence of calcium, sodium, or potassium distinguishes this mineral's plagioclase and orthoclase varieties.
This mineral is a tectosilicate whose forms are either monoclinic or triclinic. One type of this mineral corresponds to the continuous branch of Bowen's reaction series, and the angle between its two cleavage planes is used to classify it into two types. Forms of this mineral include labradorite, albite, and microcline, and the presence of calcium, sodium, or potassium distinguishes this mineral's plagioclase and orthoclase varieties. For 10 points, name this aluminum silicate mineral, the most abundant in the earth's crust.
This mineral is a tectosilicate whose forms are either monoclinic or triclinic.
Feldspar [accept Plagioclase Feldspar or Orthoclase Feldspar]