Figure 1. Left: 18K yellow gold “Flames” ring with 25.19 ct Mexican fire opal. Right: This 18K yellow gold “Spice” ring ...

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 ...

The published literature offers only a few records of direct measurement of the natural radioactivity in nephrite. The present study used high-purity germanium (HPGe) low-background gamma-ray ...

Recently the author examined a 0.95 ct diamond with a special note. It only took one and a half beats to discover a dark crystal with a straight stress cleavage crack shaped like a dotted quarter note ...

Figure 1. This gold ring with a phoenix motif features a Neyshabur turquoise (13 × 17 mm), with a 0.02 ct ruby on each side and diamond accents. Courtesy of Taktala Jewelry, Tehran. Turquoise is an ...

Descending into Peshawar for the first time, a foreign tourist might be surprised to learn that amid the clutter of buildings in this historical city lies an important gem trading center. This market ...

Diamonds have a long history as a premier gemstone—a natural consequence of their beauty, rarity, and superlative physical properties such as extreme hardness. Diamonds that are mined for use as ...

The geological landscape around us evolves so slowly that it can appear static, but the rigid tectonic plates that make up the outer layer of our planet drift across its surface over time.

Diamonds are the most amazing of gems. Just as amazing, however, is how natural diamonds reach Earth’s surface. Diamonds are formed 150 to 700 km deep in Earth, and are then carried upward in a rare ...

Figure 1. Corundum is an example of a negative uniaxial mineral. This ruby crystal in matrix from Mogok, Myanmar, is approximately 6.15 cm in length. The cut gem is a 3.22 ct unheated ruby, also from ...

Figure 1. The vivid colors seen in fine gem-quality spinel are derived from the mixing between multiple different chromophores in a range of ratios and concentrations, as in this fine 13.52 ct ...

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 ...