5.15 ct

SpeciesDiamond | Ruby
Weight5.15 cts
MetalsWhite Gold
Measurements11.23 x 9.78 x 5.76 mm
Lot Number043
PriceUSD 29,728

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This Songea ruby from Tanzania is a very well-proportioned, oval-shaped stone set in a lovely white gold ring with white diamonds. Declared at 5.15 cts, it is loupe-clean and has been heat-treated with light elements. This is a delightful example from the Songea mining area, which is still producing quality stones, but not in great quantity.


Tony Brooke Chairman

Diamond is perhaps the most famous gemstone. It has many sought after gem properties: it’s incredibly hard (10/10 on Mohs scale), brilliant, lustrous and exhibits high dispersion. Most diamonds are billions of years old and composed simply of the element carbon. Diamonds in the white range have been popularised in engagement rings since the 1940s, while fancy colours are far rarer. Diamonds are also used to complement and accentuate the allure of coloured gemstones. Diamond is the birthstone for April and for 60th and 75th anniversaries

Officially the most valuable coloured gemstone, with world record gems having achieved over one million dollars per carat at auction. Ruby is the red variety of corundum coloured by chromium, and so the sister stone to all the rest of the sapphire family. A rare gem, it is not found in large sizes, and is highly prized in royal collections. The trade term ‘Pigeon’s Blood’ is used for the best colour (and usually quality) gems with, historically, the best gems coming from Burma (Myanmar). Today, Mozambique is one of the largest producing countries. Heat treatment is not uncommon, as is heating with a flux, and much lower grade material might be fracture-filled; all of these treatments must be disclosed. Ruby is 9 on Mohs scale of hardness, and the birthstone for July.

Gembridge Members source their gem-quality stones from countries all over the world, including many famous regions and mines. While origin is not an indicator of quality, it does provide context for buyers.

Origins listed on Gembridge may be stated as an opinion on a laboratory report or described by the Seller familiar with the stone’s provenance.

Gemstones come in many different forms. On Gembridge, we describe each by its shape in simple terms – round, square, cushion etc. Where relevant, we may also list the style of cutting, such as brilliant, step etc.

Although untreated gems are highly prized, there are many universally accepted treatments that enhance a gemstone’s beauty, including heating (for colour), and oiling (for clarity). On Gembridge, all treatments must be fully disclosed, so you know exactly what kind of gemstone you are purchasing.

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Orders are shipped to you within 24 hours of collecting payment, at a flat global rate of US$ 100, unless you are buying high value stones. Gemstones can be verified before shipment and must match their cataloguing. If not, the Buyer has 72 hours after delivery to notify Gembridge, who will investigate and charge the Seller for their return.

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The HS codes for loose and set stones are:

HS Code : 7103 – Precious Stones (Other Than Diamonds) And Semiprecious Stones, Whether Or Not Worked Or Graded But Not Strung, Mounted

HS Code : 71039100 – Ruby, sapphire and emeralds

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