Golconda type IIa diamond flanked solitaire ring. Set to centre with a Golconda type IIa octagonal emerald-cut diamond, D colour, VVS1 clarity, with a weight of 2.36 carats, in an open back claw setting, flanked by two tapered baguette cut diamonds in open back rubover settings with a combined approximate weight of 0.45 carats. The total approximate diamond weight is 2.81 carats, to an impressive flanked solitaire design featuring curving corner claws, a linear pierced gallery and angular open backholing, leading to raised shoulders and flowing through to a solid D-shape shank. Tested platinum, circa 1950, accompanied by Gemological Institute of America (GIA) report #2225798012.
Diamonds are classified by scientists into two main types, depending on the presence of nitrogen in the diamond's chemical makeup. Type II diamonds contain little to no such impurities. This type is further subdivided into two groups, ‘a’ and ‘b’, both of which make up less than two percent of all gem quality diamonds. Type IIa diamonds are extremely rare, and the most pure of all diamonds, and consequently exhibit superior transparency. This type was first identified as coming out of India, namely the Golconda region. Some of the most famous diamonds in the world are Type IIa, including the Koh-i-noor and the Cullinan I.
