Southeast Vietnam has a total area of 23,000 km 2, and approximately 10,000 km 2 is covered by basaltic formations with thicknesses ranging from a few meters to over a hundred meters (figure 2) (Hoang ...

Gem News International Gems & Gemology, Spring 2025, Vol. 61, No. 1 Green Jadeite-Omphacite from Guatemala. Jennifer Stone-Sundberg, Aaron Palke, and Wim Vertriest ...

GIA scholarship application cycle is from April 15 to May 15, 2023. To apply, click the button below to learn more. GIA-administered scholarships are available for GIA campuses worldwide. • Applicants ...

According to Hole et al. (1969), the earliest Persian turquoise artifacts were discovered in the Deh Luran Plain in western Iran. Radiocarbon dating suggests that turquoise beads found in burial sites ...

As shown in figure 2, diamonds have formed over a wide range of the earth’s geologic history. The oldest dated examples are diamonds with an age of 3.5–3.3 Ga (billion years) from the Diavik and Ekati ...

In November 2022, a parcel of 24 approximately 0.5–1.2 ct spinel crystals, described as cobalt-diffused, were obtained directly from a treater by the research team at GIA in Bangkok. Of these, seven ...

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 ...

Tempskya, an extinct genus of tree ferns, thrived during the Cretaceous period and has left fossils in both the Northern and Southern hemispheres (Tidwell et al., 2010).Unlike living tree ferns, ...

Chemical vapor deposition (CVD) growth technology has advanced significantly over the last two decades. In this study, we report on the largest CVD gem diamond GIA has encountered, recently tested in ...

These diamonds are from the 2016 Argyle Pink Tender in New York City. Left to right: 0.64 ct Fancy Deep pink oval, 0.75 ct Fancy Intense purplish pink trilliant, 0.91 ct Fancy Vivid purplish pink oval ...

Diamonds from the Deep Gems & Gemology, Spring 2020, Vol. 56, No. 1 Diamonds Are Not Forever! Diamond Dissolution. Karen V. Smit and Steven B. Shirey ...

Laboratory-Grown Diamonds. Man-made diamonds suitable for industrial use were first produced in a laboratory in the 1950s. While gem-quality diamonds were produced in a laboratory for the first time ...