At the earth’s surface, graphite is the stable crystalline form of carbon, with a density of 2.26 g/cm 3. Diamond is a much more compact form of carbon, with a density of 3.52 g/cm 3, 56% higher than ...

Since its discovery at the beginning of the nineteenth century, infrared light has proven to be a versatile tool for scientists, industrialists, and consumers. The gem industry has benefited from the ...

Figure 1. Sapphires from Madagascar: a beautiful 3.29 ct untreated faceted stone and an assortment of rough in the background. Madagascar has produced many high-quality stones in the last few years ...

Filigree inlay art originated in the Warring States Period (475-221 BC). At the time, it was called “Jin Yin Cuo,” which involved painting gold and silver on the surface of bronze artworks. With the ...

Sri Lanka has two monsoon seasons that occur at different times of the year depending on the part of the country. The northeast has monsoons from December through March. In the southwest, where most ...

Aquamarine and heliodor are colored by Fe ions, an important coloring agent for beryl. Blue to yellow gem beryl was studied by quantitative spectroscopy and trace-element analytical techniques to ...

Todd’s Gems Todd Wacks outlines how garnets believed to be “regular” Tanzanian rhodolite when discovered in the late 1980s turned out to be rare color-change pyropes instead. In this video, he ...

Northern Mozambique (figure 1) has gained attention for its rubies since a major discovery near Montepuez in 2009 (see McClure and Koivula, 2009; Pardieu and Lomthong, 2009; Pardieu and Chauvire, 2012 ...

Blue zircon is perhaps best known from Cambodia, with most if not all of the material recovered as brown stones that turn blue upon heating. Recently, Brent Smith of Phoenix Gems supplied us with a ...

Diamonds, colored stones, and pearls submitted to GIA laboratories today will have services completed and be ready for return by the estimated dates noted below. Requesting additional services after ...

Delphine Bruyère, Claude Delor, Julien Raoul, Rufin Rakotondranaivo, Guillaume Wille, Nicolas Maubec, and Abdeltif Lahfid ...

With a reach that spans the globe, GIA is a nonprofit institute dedicated to protecting consumers by ensuring their trust in gems and jewelry through cutting edge gemological research, rigorous ...