PLAGIOCLASE FELDSPAR - - a group of common rock-forming feldspar minerals composed of sodium, calcium, aluminum, silicon, and oxygen, and having the formula (Na,Ca)(Al,Si)2Si2O8.
(common rock-forming feldspar minerals; composed; of sodium, calcium, aluminum, silicon, and oxygen, and having the formula) (a group of common rock-forming feldspar minerals; having; the formula)
common rock-forming feldspar minerals a group of common rock-forming feldspar minerals
composed having
of sodium, calcium, aluminum, silicon, and oxygen, and having the formula
the formula