(IDEX Online) – A white diamond described as the largest ever to appear at auction could sell for $30m.

The 228.31-ct pear-shaped gem will lead Christie’s Magnificent Jewels sale in Geneva.

The G/VS1 stone, named The Rock (pictured), was mined and polished in South Africa over 20 years ago. It has an estimate of $20m to $30m.Click here to read full article.http://www.idexonline.com/FullArticle?Id=47505#.YpcEzF35tYE.gmail