By David Brough
Digital marketplace Gembridge has listed for the first time a collection of exquisite and rare Umba sapphires, which will impress collectors and traders due to their remarkable colours.
Some Umba sapphires, which come from an area near the Umba river in Tanzania, display a colour transformation effect reminiscent of alexandrites, changing from light violet-red to light green depending on the light source.
Umba sapphires are mainly known for their range of orange-red, orange, and orangey golden yellow colours. Other colours include pink, yellow-gold, blue, purple and green. These colours are due to various elements including chromium, manganese, iron, titanium, and high proportions of vanadium.
Umba sapphires, unlike most other sapphires, are virtually never treated, which makes them rare.
The story of Umba sapphires started when, in the mid-1960s, George Papaeliopoulos, a Greek farmer living in Africa, discovered a sapphire deposit along with rhodolite, malaya garnets and emeralds near the Umba river.
Having no background in gemmology or the gems industry, he took the stones with him to Idar Oberstein, Germany’s gem trading centre.
He met Eugene Naftule, a gems trader, who offered to buy his rough.
They came to a deal in which Papaeliopoulos would export the rough from Tanzania, and the Naftule family would cut it at their workshops in Geneva and Shannon in Ireland.
At that time the cut gems ranged in size from melee to very large stones often exceeding 50 carats. The exceptional stones generated interest from many of the major jewellery houses.
In 1971, Tanzania decided to end the export of gemstones. Papaeliopoulos left Tanzania, which ended the agreement between him and the Naftule family.
The export of gemstones resumed several years later and although efforts have been made to mine corundum in the Umba area they have been largely unsuccessful.
Picture courtesy of Piat
Now, following an agreement with Roland Naftule, a well-established European dealer offers Umba sapphires.
Picture courtesy of Piat
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