The comparison between two of the world’s most important blue diamonds – the Wittelsbach-Graff and Hope diamonds has been described in an article written by Dr. Eloïse Gaillou and colleagues in the Summer 2010 issue of the Gemological Institute of America’s (GIA) Gems & Gemology.

“Because these diamonds have similar colour and long-lasting phosphorescence – and both are believed to have been purchased in India during the 17th century – there has been widespread speculation that they were cut from the same crystal,” says Alice Keller, editor-in-chief of G&G. “In this article, observations with the DiamondView and other tests demonstrate that the Hope and the Wittelsbach-Graff do not share a common parent.”

The issue also details features on the play-of-colour opal from Wegel Tena, in Ethiopia’s Wollo Province by Dr. Benjamin Rondeau and coauthors, a new type of composite turquoise, a new source of fire opal in Madagascar, X-ray computed microtomography in pearl identification and a new orangy brown gem mineral, hibonite, along with write-ups on new synthetic diamonds in the magazine’s ‘Lab Notes section’ and a the recent finds of kunzite in the Gem News International section.