Of its four basic varieties, celsian is the least frequently occurring, with its main constituent tetrahedra linked by barium ions.  
Of its four basic varieties, celsian is the least frequently occurring, with its main constituent tetrahedra linked by barium ions.  This group can be divided into two classes: the alkali, composed of microcline, orthoclase, and sanidine; and the plagioclase, composed of the pure sodium and pure calcium varieties, knows as albite and anthorite, respectively.  This group of aluminum silicates tends to form colorless, white, or pink crystals.  FTP, identify this group of minerals that rates 6 on the Mohs' hardness scale, the most abundant minerals in the earth's crust.
Of its four basic varieties, celsian is the least frequently occurring, with its main constituent tetrahedra linked by barium ions.  
feldspar