Golconda Diamond Ring. Photo M.S. Rau Antiques

This spectacular 3.02-carat Golconda diamond is among the whitest diamonds in the world, and is one of the few perfect Golconda diamonds that have ever come on the market. This enchanting pear-cut stone is classified by the Gemological Institute of America as being internally flawless, D-color, and type IIa, meaning there is no trace of nitrogen (the element that gives diamonds color), a key characteristic of all Golcondas. The Type IIa classification also means that this diamond is a full two shades whiter than a typical D-color diamond. Accented by two baguette diamonds, which weigh .25 total carats and boast G-color and VS-clarity, this gem is truly one of the world's greatest treasures. Price: $348,500

Known as the "Ultimate Diamond," this enchanting stone represents the incredibly small number of Golconda diamonds that have ever been on the market. Golconda diamonds are the purest of all, possessing levels of transparency unrivaled by any other diamond. Universally accepted as the finest diamonds in the world, Golcondas are extremely scarce. The term "Golconda" refers to the ancient city in India where the diamond trade flourished in the 18th century due to the extraordinary quality of the gems unearthed from its mines. As these mines are now extinct, Golconda diamonds are among the rarest and most precious in the world. 

M.S. Rau Antiques - www.rauantiques.com