The charts above illustrate the greater investment performance of fine diamonds of 3 carats and larger, which is what SHERWOODS recommends as (generally) the best investment vehicle for white diamonds: 3.00 carats and larger, G color, VS2 clarity and better.

This is more a general "rule of thumb" than a "hard and fast" rule though, as exceptionally attractive large diamonds of lesser color and clarity can often perform surprisingly well in investment return. The key is to buy beauty, while avoiding "problem stones". This is where the experience of SHERWOODS gemologists along with their awareness of the diamond market is of significant help to the investor.

The key is LARGE though. Large, important diamonds usually sell quicker, easier and for more profit than smaller ones in today's pyramidical environment of wealth concentration.

"Sotheby's New York annual spring auction of Magnificent Jewels on April 17 (2013) will offer 400 lots and a combined presale estimate in excess of $35 million. The centerpiece of this sale is an exceptional 74.79-carat, D, VVS1, potentially flawless, type IIa, pear-shaped diamond with a presale estimate of $9 million to $12 million."

Lisa Hubbard, the chairman of North & South America at Sothesby's International jewelry division, said, "This truly exceptional stone exemplifies the strength of the white diamond market over the last decade. It was acquired by the owner in 2001 for $4.3 million and today we have established it conservatively at$120,000 per carat. The stone has universal appeal from both the diamond industry and discerning private collectors alike."