Beryllonite crystals arc colorless, white, or pale yellow, but its weak fire and low dispersion make it a dull gemstone. In addition, its softness, perfect cleavage, and brittle fracture make it fragile, although with care it may be faceted for collectors.

Beryllonite is a pegmatite mineral, found associated with the minerals phenakite and beryline in Maine in the USA. It is also found in Finland and Zimbabwe, but remains a rare gem.

Beryllonite is named after the beryllium content in its chemical composition. It has been confused with other colorless gemstones of low dispersion .