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 imoprtant 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.




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