Crystal is a colorless and transparent crystalline mineral of quartz. Its main chemical is silica, which is a substance similar to ordinary sand. When the crystallization of silica is perfect, it is crystal; After silica gel dehydration, agate is produced; After the colloidal silica containing water solidifies, it becomes opal; When the grain size of silica is less than a few micrometers, it forms chalcedony, flint, and secondary quartzite.
A perfectly crystallized crystal belongs to the hexagonal crystal system, often in the shape of a hexagonal prism. The prism has one or two pointed ends, and multiple long prisms are connected together, commonly known as the crystal family, which is beautiful and spectacular. Silicon dioxide crystals are incomplete and have various shapes. When you go to the Hainan Crystal Exhibition Hall to take a look, it can broaden your horizons: in addition to the common long columnar shapes, there are also sword like shapes, some like plates, some like short columns, and some like double cones. Some are as small as fingers, while others are as big as boulders; Some are less than half a liang, while others weigh over 300 kilograms.
