Explanation

Island structure silicate mineral. The crystal is long plate or knife edge. Blue, gray, yellow, and light green. glass luster, pearly luster on cleavage surface. Parallel cylindrical surfaces have a set of complete cleavage. There is a set of cracks on the vertical cylindrical surface. Mohs hardness 5.5-7. The hardness of the cylinder in the direction parallel to the Z axis is 5.5, and the hardness of the cylinder in the vertical direction is 6.5, showing extremely significant anisotropy, so it is also called hard stone. Embrittlement. It is a typical regional metamorphic mineral, mostly formed by the metamorphism of mudstone. It is a high-grade refractory raw material. Those with bright colors can be used as gems.

Classification