Figure 1. Diamonds such as this 1.15 ct round brilliant are some of the most highly sought-after gem materials and may contain inclusions that give the gemologist clues about their origin or treatment ...

GIA laboratory-grown diamond services include an overall quality assessment for laboratory-grown diamonds. The GIA assessments for laboratory-grown diamonds have a distinct format to fully ...

The history of Baja California has been closely tied to the exploitation of pearls since the 16th century. Using rudimentary diving techniques for most of this era, European and Mexican entrepreneurs ...

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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. The 31.98 ct (6.40 g) rough sapphire crystal as it was mined. Photo by Jeffrey R. Hapeman. In September 2016, while viewing a selection of large Montana sapphires mined by Potentate Mining ...

North America has a long history of natural pearling owing in part to its very diverse and rich freshwater mussel resources. After the Civil War pearl jewelry gained greater popularity in the United ...

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 ...

This raspberry-and mint-colored tourmaline—nicknamed the “Steamboat”—is one of the world’s finest and most valuable mineral specimens. Photo by Duncan Pay ...

Terry Coldham (left) and Jack Wilson (right) each have more than 50 years of experience in Australian sapphire mining and trading. They shared their in-depth understanding of the Australian sapphire ...

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 ...

Earth’s surface is divided into tectonic plates, and the ones that make up the ocean floor are destined to sink. Sheets of oceanic crust typically bend and sink down into Earth’s interior at so-called ...