Gem Id Key Terms

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103 Cards. Created by karin ().


Lacking a regular crystal structure

Chemical composition

Kinds and relative quantities of atoms that make up a material

Crystal structure

Regular, repeating internal arrangement of atoms in a material

Gem species

A broad gem category based on chemical composition and crystal structure

Gem variety

A subcatagory of species, based on color, transparency, or phenomenon


A family of gems made up of several closely related mineral species

Immitation gem (simulant)

Any material that looks like a natrual gem and is used in its place.


Composed of, or arising from, non-living matter.

Isomorphoun replacement

Substitution of one chemical element for another in the crystal structure of a mineral.


A natural, inorganic substance with a characteristic chemical composition and, usually, a characteristic structure.


Produced by, or derived from, a living organism.


An unusual optical effect displayed by a gem.


Process of distinguishing natural gems from each other as well as from synthetics, simulants, and treated gems.

Synthetic gem

A labratory creation with essentially the same chemical composition, crystal structure, and properties as its natural counterpart.

Trace elements

Atoms in a gem that aren't part of its essential chemical composition.


A smooth, flat break in a gemstone parallel to planes of atomic weakness.

Conchoidal fracture

A curved and redged fracture in a gemstone, extending from the surface inward.


The seperation of white light into spectral colors.


The flashes of spectral color you see in a polished gem, expecially a diamond.


Any break in a gem other than cleavage or parting.