Most colored gemstones form near the earth’s surface in a wide range of different environments; for example, they can crystallize from igneous magmas or hydrothermal solutions, or via the ...
Zircon comes in a wide variety of colors. Colorless zircon is well known for its brilliance and flashes of multicolored light, called fire. These two zircon properties are close enough to the ...
Cultured pearls come in different sizes, shapes, and colors. Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most ...
Some mollusks (e.g. oysters) live in saltwater environments like oceans and bays, while others (e.g. certain mussels) live in freshwater environments like lakes and rivers. Pearls may form in mollusks ...
A synthetic gem material is one that is made in a laboratory, but which shares virtually all chemical, optical, and physical characteristics of its natural mineral counterpart, though in some cases, ...
This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...
GIA evaluates ruby but does not grade it. A GIA Colored Stone Identification & Origin Report assesses the characteristics of a ruby (weight, measurements, shape, cutting style and color), indicates ...