In China, many pool table merchants do not know the difference between the slate used on the pool table, so there are all kinds of names, such as marble, volcanic rock, bluestone, inkstone stone, inkstone, etc.
What kind of slate should be used for the pool table?
The theory of volcanic rock is only in China, and it is unknown where it came from (it is speculated that some merchants may have woven it in order to create something "different").
First of all, volcanic rock is impossible to use on a pool table; volcanic rock is magma formed deep in the crust or in the upper mantle, and it is formed by intrusion into the upper crust or eruption to the surface, cooling and consolidation, and crystallization. This kind of rock is often porous and light, like burnt coal slag, fragile, porous, highly absorbent, light, and heat-insulating. Volcanic rock is often only 1/4 the weight of granite or marble. After cutting and grinding, the surface of this material has a lot of holes similar to honeycombs. How can it be used on a pool table?
In addition, regarding bluestone, a more detailed explanation is needed: in China, many people like to call different blue stone types such as blue slate (SLATE), blue sandstone (SANDSTONE), blue limestone (LIMESTONE) bluestone; although these stones have the same color, their physical properties and chemical compositions are almost completely different. There is only one kind of slate recognized by the official billiards organization in the world, that is blue slate, which is called SLATE in English. It is commonly known as bluestone in the Chinese market, and some people call it inkstone stone.