Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. Chalcedony's standard chemical structure (based on the chemical structure of quartz) is SiO2 (silicon dioxide).
Chalcedony is a nurturing stone that promotes brotherhood and goodwill and enhances group stability. It can be used for telepathy and transmission. This stone absorbs negative energy and then dissipates it so that the energy doesn't move to someone else.