Merelani Mint Grossular Garnet, Tanzania. Estimate US$ 70,000 - 80,000 (€61,000 - 70,000). Photo Bonhams.

A cousin to the deep green tsavorite is a young gemstone with a very long geological history--the Mint Grossular Garnet. Its home is the East-African bushland along the border between Kenya and Tanzania. The few mines lie in a uniquely beautiful landscape of arid grassland with bare, dry hills. No other occurrences of gem material have been discovered. Such stones rarely surface on the market-

The color of this grossular garnet--like tsavorite-- is believed to be due to vanadium, at times with a trace of chromium. The present, oval-cut stone is of large size for the species: it has a true leaf green color, unmodified by yellow and entirely without extinction. It displays all the most sought-after characteristics--and is truly a stone for the serious collector. Weighing approximately 12.64 carats and measuring 13.7 x 12.2 x 8.5mm

Bonhams. LAPIDARY WORKS OF ART, GEMSTONES AND MINERALS INCLUDING GOLD, 19 May 2015 10:00 PDT - LOS ANGELES