1, obsidian, black pebble, fine coal stone, Leigong ink, black jade, etc. Obsidian, a common black gem, also known as "Dragon Crystal" and "Ten Victory Stone", is a naturally occurring silica, usually black. Obsidian can be processed into handicrafts. In addition, obsidian has the characteristics of glass, and its cross section is shell-shaped and very sharp. At present, most obsidian jewelry is produced in Central America and North America, and the national stone of Mexico is obsidian.
2. Black pebbles can be divided into Sanjiang golden pebbles, pure natural black pebbles and polished pure black pebbles. Pure natural black pebbles are collected from the river bed, without artificial pigment, with very good gloss and attractive appearance. Used for indoor decoration, bathroom floor laying, bonsai filling, etc. Common specifications of pure natural black pebbles: 2 ~ 3~5cm, 3~5cm.
3. Fine coal stone, also known as coal jade, black charcoal stone, black gem, carved lacquer coal, etc. , is a variety of lignite. It is an opaque black organic gem with strong luster, which was formed 3 million years ago. Coal jade is composed of carbon and organic matter, and its aggregate is dense and massive, and sometimes traces of branches and leaves of trees can be seen. The hardness of coal concentrate is 2.5-4, and the relative density is 1.30- 1.34. Coal concentrate can be burned, showing a flame similar to soot and emitting an unpleasant smell.