With proper care, citrine is a beautiful and versatile gemstone for jewelry use. – Robert Weldon Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or ...

Consumers now, more than ever, have a heightened awareness of sustainably and ethically sourced products. The GIA Diamond Origin Report uses scientific evaluation to provide confirmation of a ...

A peridot-like bright greenish yellow to green gem material called “green amber” has recently appeared in the gem market.

Figure 1. Left: The Blue Moon diamond as the 29.62 ct rough discovered in January 2014 at the Cullinan mine in South Africa. Right: The faceted Blue Moon diamond, a 12.03 ct cushion modified brilliant ...

Despite the commercial value of natural-color diamonds, distinguishing them from treated diamonds remains a significant identification challenge. While some diagnostic visual features exist ...

Scientific advances in the past decade have completely altered our understanding of certain concepts relating to the age and origin of diamonds. As a generalization, most diamonds formed more than 990 ...

Gem-quality synthetic or laboratory-grown diamonds are more available in today’s jewelry marketplace than ever before, causing both interest and concern about lab-grown diamonds and whether ...

Figure 1. Sapphires from Madagascar: a beautiful 3.29 ct untreated faceted stone and an assortment of rough in the background. Madagascar has produced many high-quality stones in the last few years ...

Raman spectroscopy confirmed the identity of the material as pezzottaite by an intense peak at ~1100 cm –1, which is not present in beryl. Fourier-transform infrared spectroscopy showed features ...

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 ...

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 ...

Diamonds are known for their hardness – their ability to resist scratches and abrasions. But diamonds are not impervious to damage, since their hardness is uneven along different crystal directions.