berilli
Berilli is a term encountered in a few contexts, most commonly as a plural or variant form referring to members of the beryl mineral group and occasionally as a surname or toponyms. The beryl group comprises cyclosilicate minerals with the basic chemical composition Be3Al2Si6O18 and a hexagonal crystal system.
Beryl occurs in a range of colors and gem varieties determined by trace-element impurities: emerald (green,
The name beryl derives from ancient Greek beryllos, historically used for precious blue-green stones. When used