The following article appears courtesy of GIA Gems & Gemology eBrief
Intellectual Property: Gemological Institute of America
Photo by: Robert Weldon
Author: Russell Shor
Fine rubies from outside Myanmar, such as this 14.97 ct ruby from Winza, Tanzania, continue to command top prices in the market. Courtesy Mona Lee Nesseth Custom and Estate Jewels and a private collector; photo by Robert Weldon.
Diamond demand at the recently concluded BaselWorld and Hong Kong Watch and Jewellery fairs was concentrated in the high end, with stones of more than 5 ct bringing strong prices. While a significant portion of buyers were from Asia, demand was also strong from the U.S. and Europe.
Dealers reported a perceived shortage of such goods, particularly because rough diamond production remains well below the peak levels seen before the 2008-09 economic crisis. The continued weakness of the U.S. dollar – the trading currency for diamonds – against other major currencies is also contributing to higher prices.
Prices for top rubies were also very strong because of extreme shortages of supply. The ban on Myanmar goods in the U.S. and European Union is keeping most of the best stones off the market, and dealers are holding on to top rubies from other localities in hopes that a full economic recovery will bring even stronger prices.
The major auction houses are moving to take full advantage of these trends, packing important stones into upcoming sales in Hong Kong, New York, and Geneva.
Senior Industry Analyst, GIA Carlsbad
Author: Brendan Laurs
Intellectual property: GIA
Photo by: Robert Weldon
This cat’s-eye rhodonite (6.93 ct) from Brazil shows good chatoyancy. Photo by Robert Weldon.
Gems & Gemology editor Brendan Laurs prepared the following entry for the G&G Gem News International section.
Rhodonite (MnSiO3) is an attractive pink-to-red mineral that is often sold as specimens or ornamental material, but seldom as a gemstone, since it is typically opaque and has perfect cleavage in two directions. Facetable material is very rare, and small amounts are occasionally produced from just two localities — Broken Hill, Australia, and Minas Gerais, Brazil. Some polished material has a saturated color that resembles fine spinel or rhodochrosite.
At last month’s Gem & Jewelry Exchange show in Tucson, Luciana Barbosa (Gemological Center, Belo Horizonte, Brazil) had some attractive rhodonite cabochons showing good chatoyancy (e.g., see figure). She reported that the material was found in 2009 at Morro da Mina, near Conselheiro Lafaiete in Minas Gerais. The rhodonite is recovered as a byproduct of manganese mining, in a large open pit operated by Companhia Vale do Rio Doce. Barbosa knew of about 30 pieces of the cat’s-eye rhodonite (ranging from approximately 2 to 40 ct), and she had not seen the material previously. To her knowledge, the stones were all untreated. She indicated that the identity of the rhodonite was confirmed with X-ray diffraction analysis.
We believe this is the first report of cat’s-eye rhodonite.
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