3.96 ct. South African Tephroite
Color: Dark Greyish-Green / Reddish-Brown
Origin: Kalahari Manganese Fields, South Africa
Cut: Rectangular Tablet
Measurements: 10.7 x 7.1 mm
A fascinating stone for the collector of ultimate rarities. Tephroite is, in fact, the rarest member of the Olivine group of minerals that contains Forsterite (of which most gem Peridot is primarily comprised) and Fayalite as well. Until a tiny find of crystals in South Africa (Wessels and N’Chwaning) there was almost no known examples of Tephroite being used as a gem material; this gemological curiosity was written up for the Journal of Gemmology and a lab note is published in vol. 36 (2018). Crystals are almost always opaque and heavily fractured, but a few were deemed translucent and durable enough to attempt to cut a few stones - this gem is one the largest and finest cut from these attempts. Beyond the obvious rarity of the material is the unique color change it possesses - not something one would expect from a close relative of Peridot. Cut as a rectangular tablet this stone has a striking change from grey-green to reddish-brown; it is nicely translucent and well proportioned. Extremely rare.