Rare blue diamond to be auctioned in HK  

无瑕稀有 世界最大圆形鲜彩蓝钻将在港拍卖(图)

(ECNS) -- A rare 7.59-carat round blue diamond, known as "The Premier Blue," will go under the hammer in Hong Kong on Oct. 7, according to Hong Kong-based takungpao.com.

Sotheby's Hong Kong auction house said the diamond has not been priced yet, and it is unique in so many ways, including the round cut rarely used in colored stones because of the high wastage, fancy vivid blue and high-level purity.

"The Premier Blue" is defined by the Gemological Institute of America (GIA) as the biggest round fancy vivid blue diamond, Sotheby's said.

The term "fancy" is used to describe a diamond of intense color, while a gem's saturation grading ranges from light to vivid for colored diamonds.

The diamond was exhibited in Asia, Geneva, London, New York and Doha.

In October 2011, a 6.01-carat fancy vivid blue cushion-cut diamond ring garnered $10.1 million and set a world record price per carat for any fancy vivid blue diamond.