Synthetic alexandrite crystals are made by flux-fusion method by annexing Fe, and Cr manufactured in USA and Japan.
See Alexandrite Tsarstone collectors guide, Definition of Flux-grown synthetic alexandrite, http://w.alexandrite.net/viewpage.html?id=GG-091-00005 (Synthetic alexandrite crystals are made by flux-fusion method by annexing Fe, and Cr manufactured in USA and Japan.) (as of Apr. 09, 2026, 09:46 GMT).