Perlite perlite is a kind of vitrified rock formed by volcanic eruption and rapid cooling, which is named for its pearl fissure structure. Perlite deposits include perlite, obsidian and turpentine. The difference between the three is that perlite has arc-shaped cracks formed by condensation, which is called perlite structure, with water content of 2 ~ 6%; The turpentine has a unique turpentine luster with a water content of 6 ~ 10%; Obsidian has glassy luster and shell fracture, and its water content is generally less than 2%.

　　It is mainly composed of massive, porous and pumice pearlite, containing a small amount of phenocrysts and microcrystals of diorthosite and quartz, and various forms of microcrystals, cryptocrystalline minerals, hornblende and other arc-shaped cracks. The fracture surface is uneven, pearl luster, oil luster after weathering, and white streaks.

　　It is mainly composed of turpentine, hydrolyzed turpentine and hydrated turpentine. It contains a small amount of diorthosite and white tuff material, which is irregularly distributed. The fracture surface is shell like, with turpentine luster and white streaks.

　　It is mainly composed of obsidian, obsidian porphyry and hydrated obsidian. It contains a small amount of quartz and feldspar phenocrysts, and a very small amount of opaque magnetite and corundum. The fracture surface is flat or shell shaped, and some of them are uneven. It has glassy luster. After weathering, it has grease luster and white streaks.