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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 ...

Yogo Gulch, discovered more than 100 years ago, is one of four major sapphire-producing areas in Montana, United States. Yogo sapphires are known for their uniform, well-saturated blue color; relative ...

GIA is a trusted authority known for its rigorous, objective analysis of both natural and cultured pearls. Learn about how ...

Figure 1. Pleochroism in a 15 ct tanzanite, as seen with the unaided eye through the crown and the pavilion sides and ends. Photo by Wimon Manorotkul. In describing colored gemstones, the major ...

Gem-quality diaspore occupies an important position in the gem market due to its rarity, striking pleochroism, and color-change phenomenon (figure 1). The material’s value depends on these factors. A ...

For centuries, the Mogok Stone Tract of Burma has provided the world with its finest rubies. The mining district is situated about 700 km north of the capital city of Rangoon, with the rubies found ...

Masters of Physics with Honors, University of Warwick, United Kingdom, 2007 Ph.D. in Physics, University of Warwick, United Kingdom, 2011 ...

This chart focuses primarily on the types of natural inclusions found in tourmaline, as well as the minerals in which tourmaline can be found as an inclusion. Treatments such as enhancement of ...

With the increasing use of radiation to color enhance gemstones, the issue of radioactivity has become a source of concern for gemologists worldwide. This article examines the basic characteristics of ...

Irradiated South Sea cultured pearls (SSCPs) from the Pinctada maxima mollusk typically show colors from light gray to silver. It is difficult to identify gamma-ray irradiation of SSCPs using standard ...

Each diamond is examined anonymously by several trained graders to ensure the objective and consistent application of GIA standards like the 4Cs of Diamond Quality and the International Diamond ...