The most prevalent and plentiful mineral on Earth is quartz. It is present in practically all geological settings and makes up at least a portion of almost all rock types. It is formed of trigonal crystalline silica and has a hexagonal crystal structure. In terms of variety, colours, and forms, it is the most diversified.
The most significant difference between the two varieties of quartz is that one is macrocrystalline, meaning that individual crystals are visible to the naked eye, and the other is microcrystalline, also known as cryptodrystalline varieties, meaning that aggregates of crystals are only visible when viewed under a powerful microscope. The general name for cryptocrystalline quartz is chalcedony. The cryptocrystalline types are either translucent or primarily opaque, with the transparent form typically being macrocrystalline.