Lacking a regular crystal structure
Kinds and relative quantities of atoms that make up a material
Regular, repeating internal arrangement of atoms in a material
A broad gem category based on chemical composition and crystal structure
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.
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.
A labratory creation with essentially the same chemical composition, crystal structure, and properties as its natural counterpart.
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.
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.