Mineral Species: Albite var. Cleavelandite

Chemical Formula: NaAlSi3O8

Chemical Name: Sodium Aluminium Silicate

Mineral Class: Tectosilicate

Mineral Notes: Albite is a common feldspar and is the key mineral of two different feldspar series. It is most often associated with the plagioclases where it is an end member. These feldspars range in chemical composition from NaAlSi3O8 to CaAl2Si2O8. The various plagioclase feldspars are identified from each other by gradations in refractive index and density. Albite is also an end member of the K-feldspars which ranges from NaAlSi3O8 to KAlSi3O8. Cleavelandite is characterised by a white and lamellar structure. It is named after Parker Cleaveland, a professor of geology and mineralogy at Bowdoin College in Maine during the early 1800s.

Description: A cluster of upright Cleavelandite crystals of notable size and form. The mineral is unusually very transparent making it appear quite gemmy. The surface is covered by small crystals of Pyrite which provides a very aesthetic contrast. A very good diplay specimen of a rare form of Albite.

Location: Morro Velho Gold Mine, Nova Lima, Minas Gerais, Brazil.