The Summer 2015 issue of GIA’s quarterly professional journal, Gems & Gemology (G&G), takes a deep look at gem inclusions.
The issue, which is now available in print and online, looks at how gem inclusions are documented using modern digital photography and image-processing software, how some interact with light inside a fashioned gem to produce a rare form of asterism, and the value that might be gained by studying them.
In addition the Summer 2015 edition debuts a new quarterly column on gem inclusions called “Micro-World” and features an examination of corundum from Tajikstan.
G&G’s cover story Digital Photomicrography for Gemologists offers basic image-capture techniques and tips to get the most out of gem photomicrographs by applying digital processing. The article by Nathan Renfro, analytical manager of GIA’s gem identification department, builds on the landmark 2003 paper by his longtime mentor and master of inclusion photography John Koivula, GIA’s analytical microscopist, to offer a highly practical and relevant guide for the gemologist.
Next, a team led by independent researcher Dr. Karl Schmetzer offers a comprehensive description of the dual-color “double stars” observed in some natural sapphire, ruby and quartz, as well as synthetic corundum, including diffusion-treated examples. The issue’s third article, by Dr. Elena Sorokina of the Fedorovsky All-Russian Research Institute of Mineral Resources and her coauthors, provides an update on the geology, mining and internal and external features of ruby and sapphire from Snezhnoe, Tajikistan.
The issue also features G&G’s regular Lab Notes and Gem News International sections, which include entries from the 2015 Tucson shows and a report of the recent Maine pegmatite workshop. In the inaugural Micro-World column, section editors Nathan Renfro, Elise Skalwold and John Koivula provide concise reports accompanied by stunning photomicrographs of specially chosen specimens, inviting gemologists to take a closer look at the astounding beauty and variety of inclusions in gems.
G&G’s free archive containing every issue from 1934 to present, more in-depth coverage, hundreds of additional photos, and exclusive video footage are available on GIA’s website.