Hazy Spinel from Mahenge, Tanzania

Ma C1. Rossman GR1, Williams B2, Williams C2, Laurs BM3

 
1 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA

2 Stone Group Laboratories, Jefferson City, Missouri, USA

3 Journal of Gemmology

Abstract

The Mahenge region of Tanzania has been an important source of attractive pink-to-red spinel. Recently, three spinels with hazy appearances were investigated to determine the origin of the hazyness. The orgin was found to be micro- to nano-inclusions that were highly enriched in titanium. These inclusions are believed to be TiO2 but attempts to determine if they were rutile or anatase were not successful.


Hazy Spinel

SEM image of a titanium oxide nano-inclusion (bright area) near the surface of a hazy spinel. The dark lines are polishing lines from the abrasive used to polish the surface.