corundum, geology.11, Mozambique.12, gems

Corundum has been known in Mozambique since the Portuguese colonial times (Afonso, R.S., Marques, J.M. , 1998, Lächelt, S., 2004) but very little information has been published about rubies or sapphires from Mozambique in the gemological literature as the production was so small and most of the stones produced were cabochon quality at best. Nevertheless, the gem markets in Bangkok and other places have recently started to see an increase in rubies coming out of Mozambique. Most of the stones seen were heavily fractured and mainly used as a base material for lead glass treatment, but some stones seen at the GIA Laboratories in Bangkok, New York and Carlsbad were fine enough to be faceted and used in jewelry without any treatment. A preliminary study on rubies reportedly from the Niassa province was released by GIA gemologists on March 22nd 2009 (Pardieu, V.P., Thanachakaphad, J. , 2009). After some inquiries it soon became apparent that there were several sources and a GIA Field Expedition to the various ruby mining areas of Northern Mozambique took place and is still ongoing at the end of 2009. Rubies and sapphires in Northern Mozambique have been mined from 4 different deposits, 3 of them located in the Niassa province and one in the Cabo Delgado province, over recent years.