Chrysoberyl (variety Alexandrite) in schist, Campo Formosa, Bahia, Brazil

Here is a classic Brazilian mineral specimen: a nice alexandrite crystal cluster. Alexandrite is a special variety of chrysoberyl that changes colour when exposed to different light sources. For alexandrite, it is red in incandescent (artificial) light - as seen in these photos - but will be green in strong daylight. Most of the material from Bahia is opaque and included like this specimen but the colour change is certainly fun. I personally enjoy gem minerals still embedded in their host rock too. I feel this gives the specimen better geologic context for understanding its formation. This specimen's matrix is composed of schist which reveals a metamorphic environment of formation. Ex Rob Belcher collection. Mounted on an acrylic base. From: Campo Formosa, Bahia, Brazil. Dimensions: 5.5 cm x 4.5 cm