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 ...

Rough pink diamonds are rarely found, and although the cause of color has been correlated with plastic deformation, the precise mechanism and atomic configuration for the resulting color are topics of ...

Gem-quality diaspore occupies an important position in the gem market due to its rarity, striking pleochroism, and color-change phenomenon (figure 1). The material’s value depends on these factors. A ...

The Karowe Diamond Mine in Botswana, owned and operated by Lucara Diamond Corp., has gained international recognition for producing large, high-quality type IaB or coexistence of IaB with IIa diamonds ...

Chemical vapor deposition (CVD) technology has been widely used to grow diamonds for the jewelry market, targeting popular colors and sizes. The majority of these products are colorless to ...

CARLSBAD, Calif. – June 2, 2025 – Beginning later this year, GIA (the Gemological Institute of America) will start using descriptive terms to characterize the quality of laboratory-grown diamonds and ...

Each summer, when the waters off Florida’s east coast are calm enough for shallow diving, treasure hunters from 1715 Fleet Queens Jewels explore the seafloor for artifacts lost in a Spanish shipwreck ...

This chart focuses primarily on the types of natural inclusions found in tourmaline, as well as the minerals in which tourmaline can be found as an inclusion. Treatments such as enhancement of ...

The micro-world of gems lies at the very core of gemology. Information gathered from observations through the microscope serves as the very foundation for many conclusions drawn on a specimen, ...

Figure 1. This group of rock crystal quartz from Brazil shows vibrant blue dumortierite inclusions. The largest rough crystal weighs 139.79 ct, and the faceted stone weighs 15.47 ct. Photo by Kevin ...

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 ...

There are two types of high-pressure, high-temperature processes related to diamond: HPHT treatment and HPHT diamond growth. HPHT laboratory-grown diamonds were developed in the mid-1950s, with the ...