A misleading term for both suitably colored synthetic sapphire and spinel, which are used to create alexandrite doublet.
See Alexandrite Tsarstone collectors guide, Definition of Alexandrite doublet, http://w.alexandrite.com/viewpage.html?id=GG-086-00004 (A misleading term for both suitably colored synthetic sapphire and spinel, which are used to create alexandrite doublet.) (as of Jul. 30, 2026, 08:56 GMT).