誕生石は、楽しくて人気のあるカラフルな方法で宝石の世界へと導いてくれます。性別、年齢、国籍、宗教を問わず、世界中の人々を魅了します。誕生石は、それぞれの宝石特有の秘密 ...

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 ...

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 ...

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 ...

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 ...

Gem inclusions are mineral crystals or cavities filled with fluid and/or gas that occur in a host gemstone. Many gems contain microscopic inclusions (ranging in size from >1 mm down to submicroscopic ...

Figure 1. Strands of Nigerian beryl in assorted colors. Photo by Kevin Schumacher. During the JCK show in Tucson, GIA had the opportunity to meet up with Amina Egwuatu, founder of Mina Stones. Mrs.

The mantle below the oldest crustal rocks of Earth’s continents has been attached to the crust since the time the crust formed. This fact is known from isotopic age dating, and it generally means that ...

White pearls and those with very light hues are routinely processed or treated by various methods after harvest, especially akoya and freshwater cultured pearls. Bleaching is the most prevalent and is ...

Figure 1. This 19.44 ct orangy pink rhodochrosite contains a four-rayed star. Photo by Diego Sanchez. The Carlsbad laboratory received a 19.44 ct semitransparent orangy pink round cabochon for ...

Carbon is one of the most important elements on our planet, which led the Geological Society of London to name 2019 the Year of Carbon. Diamonds are a main host for carbon in the deep earth and also ...