Colored Gemstones: Identity, Beauty & Documentation
Colored gemstones bring together material identity, appearance, and a wide range of individual characteristics. A familiar name is only the beginning of understanding a stone.
Read article →Gemstone Education
Ruby: Color, Identity & Treatment
Ruby is the red variety of corundum. Its color can make a strong first impression, but the material's identity, formation history, and treatment information deserve attention alongside its appearance.
Read article →Sapphire: More Than Blue
Sapphire belongs to the corundum family. Blue is its best-known color, but sapphires also occur in a range of other colors. Red corundum is called ruby.
Read article →Emerald: Understanding Identity and Enhancement
Emerald is a green variety of beryl, the mineral family that also includes aquamarine. Its individual appearance may combine color, transparency, and visible internal characteristics in ways that differ from stone to stone.
Read article →Jade: A Precise Name for a Complex Category
Jade is a familiar word that can cover different gem materials and many kinds of objects. Jadeite and nephrite are widely recognized jade materials, and GIA also discusses omphacite within the category.
Read article →Pearls: Natural, Cultured and Imitation
Pearls require terminology that reflects how they formed. Natural and cultured pearls are produced through biological processes, while imitation pearls are a different category of material.
Read article →Spinel: A Gemstone with Its Own Identity
Spinel occurs in a range of colors, including red, pink, blue, and other hues. Historically, red spinel has sometimes been confused with ruby, illustrating why resemblance is not a substitute for identification.
Read article →Tourmaline: Color, Variety & Trade Names
Tourmaline is a mineral group known for a wide range of colors. Individual stones may show one color or more than one, creating varied visual appearances within the group.
Read article →Alexandrite: Understanding Color Change
Alexandrite is a variety of chrysoberyl associated with a change in apparent color under different lighting. It is known for this optical effect, but observing color change is not enough to identify an unknown stone as alexandrite.
Read article →Opal: Play-of-Color, Identity & Construction
Opal is associated with distinctive appearances, including play-of-color in precious opal. Its beauty can be immediate, while its material description and construction deserve closer attention.
Read article →Aquamarine: A Blue Variety of Beryl
Aquamarine is the blue to greenish-blue variety of beryl. It shares its mineral family with emerald while presenting a different color identity.
Read article →Gemstone Treatments: Reading the Full Story
Treatment is an important part of many gemstone descriptions. It may affect appearance, care, and the way a stone is represented in a transaction.
Read article →Geographic Origin and Provenance
A geographic origin opinion and a record of provenance are different kinds of information. Both may matter to a gemstone's story, but they should not be used as though they are interchangeable.
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