Renewed interest in large-scale commercial mining of Montana sapphires motivated a detailed study of the heat treatment of sapphire from the Rock Creek deposit. During the course of this systematic ...

During the past 25 years, the corundum market has been transformed from one of medium to high-priced gems to one that encompasses nearly all price ranges. This transformation was caused by the ...

The various techniques in use today to alter colorless topaz to produce brown, pink, and most commonly, blue stones are discussed. Special attention is given to the three irradiation sources -gamma ...

Pearls are one of the most popular gem materials, but only in the past few decades has technology advanced to the point that good-quality imitations could be made. The Majorica S.A. product is ...

Both vibrational Raman and FTIR spectroscopy have been widely applied in identifying synthetic and natural beryl (Wood and Nassau, 1968; Schmetzer and Kiefert, 1990; Huong et al., 2010). These methods ...

Treated cultured pearls with a “chocolate” coloration have entered the market from several sources. Gemological, spectroscopic, and chemical analyses were performed on both untreated and treated ...

The cutter took full advantage of this iolite’s color and transparency, fashioning it into a uniquely carved gem, ready for use in jewelry. – Lydia Dyer, Gem courtesy John Dyer & Co. Affordable and ...

In recent years, significant amounts of gem-quality sodalite/hackmanite—some unusually transparent—have been produced from the Mogok region of Myanmar and ...

In recent years, the obligation to fully disclose all gem treatments has changed from a mere ethical responsibility to a legal one. The U.S. Federal Trade Commission Guides for the gem and jewelry ...

Some natural opals, mostly from Ethiopia, show a macroscopic finger-like structure called a digit pattern. This pattern consists of vertical columns that are more or less parallel, separated by a ...

Researchers treated 128 emeralds with nine emerald fillers—Araldite 6010, cedarwood oil, paraffin oil, unhardened and surface-hardened Opticon, a mixture of cedarwood oil and Canada balsam, ...

Figure 1. Since 1940, Richard T. Liddicoat’s contributions to gemological education, diamond quality grading, gem identification, and gemological research and instrument development have advanced the ...