Explanation

It is also called charm stone, commonly known as flim, a dense and hard cryptocrystalline or microcrystalline siliceous rock with shell like fracture. It is mainly composed of chalcedony and authigenic granular quartze or opal, and is also commonly mixed with clay mineral, carbonates, organic matter and a small amount of siliceous bioclasts. There are shell like or porcelain like fractures, with common colors such as gray, grayish black, and black, as well as yellow white, yellow, and maroon. According to occurrence, it can be divided into layered chert rock and nodular chert rock. It can be used as grinding materials, such as oilstone and fine grinding stone. Those with beautiful colors can be used as gemstones. It can also be used as a siliceous raw material for industrial use.

Classification