Blue Diamonds Described

Larger blue diamonds have achieved record prices at auction in recent years. In October 2010, a 10.95 carat fancy vivid blue diamond, the “Bulgari Blue,” broke auction records selling for $15.7 million at Christie’s. In October 2011, a 6.01 carat fancy vivid blue diamond ring fetched $10.1 million–setting a world record price per carat for diamonds of its type sold at auction. Blue diamond’s great and small are priced according to rarity, and it is not uncommon to find stones under .25 carats with 5-digit prices.

The Hope Diamond

The Hope diamond is the most famous blue diamond in the world. GIA graded the 45.52 carat stone as fancy deep greyish blue. The Hope diamond is a rare Type IIb with a unique orange-red phosphorescence.

Blue Diamond Price

Natural blue diamonds are exceptionally rare and also pose a challenge to diamond cutters. In most cases, the rough diamonds are asymmetrical making it tricky for cutters to assess exactly how the diamond should be cut and polished. Blue diamonds can also have color zoning – this is where the color is irregular throughout the stone, with areas that are more intense than others. The goal is to strike a balance between retaining carat weight and unleashing the best color possible from the diamond and color zoning can make this difficult.

As is the case with all diamonds, the price of a blue diamond is entirely dependent upon the carat weight, cut, clarity, and color. Lighter colors or blue diamonds with modifiers will be more affordable than pure color diamonds.

Blue Diamond Color

A natural blue diamond forms the same way as any other diamond; deep beneath the earth’s surface, intense pressure and heat crystallize carbon in a process that takes billions of years. It is the presence of the trace element boron in the diamond’s carbon composition that causes color in blue diamonds. The shade of blue can vary greatly, from delicate light blue to deep blue. Hydrogen can also cause greyish blue color in diamonds, as hydrogen is generally the cause of grey and even violet color. Greenish blue or green-blue diamonds also contain trace nitrogen impurities (it is nitrogen that causes yellow in diamonds).

Less than a handful of diamond mines in the world have yielded blue diamonds; the Cullinan Mine in South Africa, the Golconda in India, and the Argyle mine in Australia. Light blue diamonds have been very occasionally found in Sierra Leone. In each of these areas, blue diamonds have been the subject of much intrigue and lore. From ‘the curse’ of The Hope diamond to robberies and myth, blue diamonds carry beauty, history, and stories from across the globe.