colored stone
Any gem material other than diamond.
gemology
The study of gems.
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organic
Once living, or produced by a living organism (plant or animal).
minerals
A natural, inorganic substance with a characteristic chemical composition and usually
characteristic structure.
inorganic
Composed of, or arising from, non-living matter.
chemical compositions
Kinds and relative quantities of atoms that make up a material.
durability
A gemstone’s ability to withstand wear, heat, and chemicals.
luster
The appearance of a material's surface in reflected light.
transparency
Degree to which a material allows light to pass through it.
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hardness
How well a gemstone resists scratches and abrasion.
toughness
How well a gemstone resists breaking, chipping, and cracking.
stability
How well a gemstone resists the effects of light, heat, and chemicals.
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crystal structure
Regular, repeating internal arrangement of atoms in a material.
chemical formula
Written description of a material’s chemical makeup.
trace elements
Atoms in a gem that aren’t part of its essential chemical composition.
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crystal structure
Regular, repeating internal arrangement of atoms in a material.
amorphous
Lacking a regular crystal structure.
species
A broad gem category based on chemical composition and crystal structure.
variety
A subcategory of species based on color, transparency, or phenomenon.
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An unusual optical effect displayed by a gem.
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groups
A family of gems from several closely related mineral species.
natural gems
Gems produced by natural processes, without human help.
lab-grown gem
A manmade (synthetic) gem with essentially the same chemical composition, crystal structure, and properties as its natural counterpart.
federal trade commission
A US government agency that issues guidelines for the jewelry trade.
