Explanation

Island structure silicate mineral. Chemical formula: Al2 [Si() 4=() "often contains Mn, Fe and carbonaceous. Orthorhombic system, space group D] 2h Pnnm. Cylindrical crystal, nearly square in cross section, often presents a radial aggregate (called chrysanthemum stone) . During the growth process, andalusite often captures some carbon and clay substances in a directional arrangement? The distribution of i in the longitudinal direction is consistent with the elongation direction of the column, and it appears as a black cross in the cross-section, known as hollow crystal. Grey, with Mn and Fe present in a light rose red color, and also in yellow and green colors. After weathering, it appears gray. The glass luster "parallel {110} i" has two groups of medium cleavage. The Mohs hardness is 6.5 × 7.5, and the density is 3.15 × I 3.16 g/cm3. The typical contact thermal metamorphic mineral is produced in the contact zone between argillaceous rocks and intruders. It is the raw material of aluminum refractory. The bright pink can be used as gems.

Classification