How to tell blue gems apart
Color alone rarely identifies a gem: the same shade can come from several minerals, and some stones are treated to change their color. A gemologist uses tests such as refractive index and specific gravity. For a valuable stone, ask for a report from an independent lab.
Other colors: Red · Pink · Orange · Yellow · Green · Purple · Brown · Black · White and colorless
Colors: AGS birthstone guides. Hardness: GIA care guides. Checked October 16, 2026.