Winter 2023 G&G Available Now
January 26, 2024
The Winter issue of Gems & Gemology is bursting with exciting new content! In addition to three feature articles, it offers a field report, a new inclusions chart, the latest installment of Colored Stones Unearthed, and as always, our regular quarterly sections.
TOPAZ FROM MASON COUNTY, TEXAS
A team led by Dr. Roy Bassoo reports on Texas topaz, covering the gem’s mining history in Mason County, followed by a study of its gemological and compositional characteristics. The authors also use machine learning and statistical modeling of trace element data from worldwide topaz sources to provide a basis for determining geographic provenance.
BOHEMIAN GARNETS AS DECORATIVE MATERIALS FOR GLASS VESSELS FROM THE LATE SIXTEENTH TO EARLY EIGHTEENTH CENTURIES
Dr. Karl Schmetzer and fellow authors research a method of setting cut garnets on glass objects, examining vessels at two museums in Germany. The article begins with the historical and legal context of the technique, invented by Claudius vom Creutz in Nuremberg circa 1591, followed by the results of their study.
A UNIQUE PETRIFIED TREE FERN FROM NORTHEAST CHINA
A petrified tree fern fossil from the Cretaceous period has drawn attention since its discovery in northeast China in 2010. Ying Yan and coauthors share their study of six samples displaying golden yellow to brown colors and distinct plant structure patterns, identifying chalcedony as the primary mineral component in the material.
SLOVAK OPAL: A NEW LIFE FOR A HISTORICAL GEM
This field report by Dr. Peter Semrád follows the resurgence of opal mining in Slovakia, which yields both precious and common varieties. Historical, geological, and mineralogical details are followed by accounts of recent mining and production based on the author’s visit to the locality and interviews with heads of the country’s two main opal producers.
MICRO-FEATURES OF BERYL CHART
Nathan Renfro, John Koivula, and coauthors add to the G&G series of micro-feature charts with this display of inclusions found in natural beryl. The wall chart, which presents 30 superb photomicrographs, is included in every printed copy of this issue, and a laminated version is available for sale in the GIA Store.LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including a unique bicolor natural diamond exhibiting two distinctly different colors, a natural saltwater pearl containing a pair of foraminifera-like spheres, and a rare encounter with a large faceted orange-yellow sodalite.
MICRO-WORLD
The Micro-World section, which showcases the inner beauty of gemstones, features a stunning “sun spangle” in amber, a cross pattern visible in a natural diamond, remarkable hollandite crystals in a Brazilian amethyst, and more.
COLORED STONES UNEARTHED
Colored Stones Unearthed returns to explore the formation of sedimentary rocks, gems formed in sedimentary environments, and gems found in sedimentary environments that formed elsewhere. The column also covers the alluvial mining of these gems.
GEM NEWS INTERNATIONAL
Finally, Gem News International contributors report on a variety of topics, including a Vietnamese garnet displaying 14 trapiche patterns, an update on Virtu Gem’s ethical supply chain practices, and a summary of the fall 2023 auction season, which was marked by several surprising twists.
Erica Zaidman is associate editor of Gems & Gemology at GIA in Carlsbad, California.
