THE MINERAL NATROJAROSITE


Natrojarosite is a somewhat rare sulfate mineral. It is closely related to the mineral jarosite. Jarosite is isostructural with natrojarosite which means that they have the same crystal structure but different chemistries. In this case, jarosite contains potassium instead of natrojarosite's sodium (natro is derived from the Latin for sodium, natrium, from where sodium gets its symbol, Na). The two minerals are difficult to distinguish without a chemical test.

Both minerals are isostructural with alunite with a formula of KAl3(SO4)2(OH)6, who lends its name to the Alunite Group of which all three minerals belong.

The symmetry of natrojarosite is the same as the members of the Tourmaline Group. Crystals of natrojarosite however do not form prismatic crystals like those of the typical tourmaline mineral. Natrojarosite's crystals are more flattened and resemble nearly cubic rhombohedrons. The "rhombohedrons" are actually a combination of two trigonal pyramids. Unfortunately crystals of natrojarosite are rather scarce.

PHYSICAL CHARACTERISTICS:

 

Google
 

Copyright ©1995-2007 by Amethyst Galleries, Inc.
Site design & programming by galleries.com web services