A close intergrowth of two of these minerals, whose differentiation requires X-ray diffraction, is called cryptoperthite.
The sunstone and moonstone gems belong to this class of minerals. A close intergrowth of two of these minerals, whose differentiation requires X-ray diffraction, is called cryptoperthite. By reacting with sulfuric acid and molten sodium chloride, the potassium in sanidine is replaced by sodium to form albite, both members of this class. The intrusive igneous rock anorthosite is mainly made up of one of these minerals called labradorite. One member of this class is used as a standard of six on the Mohs hardness scale. For 10 points, name this mineral that makes up about 60% of the Earth's crust, which has orthoclase and plagioclase types.
The sunstone and moonstone gems belong to this class of minerals.
feldspars