With the exception of imperial jadeite and certain rare colors of diamond, Ruby is the most expensive gem. But like all gem materials, low-quality pieces may be available for a few dollars per carat. These stones are generally not clean enough to facet.
For a Ruby, the intensity of the red color is the primary factor in determining value. The ideal stone displays an intense, rich crimson without being too light or too dark. Stones which are too dark and garnet in appearance, or too light in color, are less highly valued. The finest rubies display a color similar to that of a red traffic light.
Large Rubies of quality are far more rare than large Sapphires of equal quality. Any untreated Ruby of quality above two carats is a rare stone; untreated Rubies of fine quality above five carats are world-class pieces.
The highest price per carat ever paid for a ruby was set on February 15, 2006 when a London jeweler, Laurence Graff, paid $3.6 million for an 8.62-carat ruby, set in a Bulgari ring. This was a record $425,000 per carat.
Less than a year before, on April 12, 2005, an 8.01-carat faceted stone sold for $274,656 per carat for a price of $2.2 million. The previous record for per-carat price was held by Alan Caplan’s Mogok Ruby. The 15.97 carat faced stone was also sold to Laurence Graff for $227,301 per carat.
Resources:
WWW.RUBY-SAPPHIRE.COM
WWW.RUBIES.COM
WWW.EHOW.COM