2. Different characteristics: The crystal of black crystal is usually large, ranging from several millimeters to several meters. China's black texture is natural, heavy and solemn.
3, different texture: black crystal impurities, the less cracks, the better. Black crystal products with good texture should not see gas-liquid inclusions or jade particles distributed in stars, clouds and flocs. China black has a high hardness, and its Mohs hardness is 7. If you use an ordinary knife, you can't mark it.
Extended data:
Precautions for using carbon black:
1, users should try to prevent dark cracks, black scars and color differences. In addition, users need to pay attention to the composition of stone to prevent stone from containing excessive harmful substances such as iron sulfide, iron oxide, salt, carbon and clay. Prevent stone from containing radioactive components.
2. Prevent the stone from containing mineral components with high thermal expansion coefficient, thermal conductivity and electrical conductivity, so as to prevent the risks of cracks, thermal conductivity and electrical conductivity.
3. When China Blackstone is used as decoration material, it is generally required that the stone should have the same vitality as the structure, especially when it is used as exterior wall and ground decoration, its durability is more important.
Baidu encyclopedia-black crystal
Baidu Encyclopedia-China Black