Monday, 21 December 2020

Umba Sapphire

The most famous Tanzanian sapphires are 'African padparadschas.'
Umba sapphire is a unique type of sapphire discovered in 1962 in the Gerevi Hills, north of the Umba River in the Umba Valley of Tanzania. Umba sapphires exhibit coloration not common to sapphires sourced from other parts of the world. At a small bend in the Umba River near the Kenyan border, a unique two-mile-radius deposit produces just about every color of sapphire imaginable.
Umba sapphires are mainly known for their range of orange-red, orange, and orangy golden yellow colors. These unique colors are due to various coloring elements including chromium, manganese, iron , titanium, and high proportions of vanadium.
The gem gravel of the Umba River Valley has been a major source of sapphires for at least a half century. The area also yields rare color-change sapphires.