Term
|
Definition
| light is bent upon entering the stone |
|
|
Term
|
Definition
| light is bounced off the facets of the stone |
|
|
Term
|
Definition
| differential bending of different wavelengths of light; when white light passes through a prism |
|
|
Term
|
Definition
| "self-colored," natural color of gem |
|
|
Term
|
Definition
| "other-colored," colored by an element or impurity that is not an essential part of its chemical composition |
|
|
Term
|
Definition
| rainbow effect, caused by dispersion |
|
|
Term
|
Definition
| change in color due to change in lighting |
|
|
Term
|
Definition
| change in color under UV light |
|
|
Term
|
Definition
| after-glow of gem after UV light is turned off |
|
|
Term
|
Definition
|
|
Term
|
Definition
| cat's eye effect, silky appearance |
|
|
Term
|
Definition
| needle-like inclusions forming star shape |
|
|
Term
|
Definition
| measures difference between RI of red light and RI of violet light; the degree at which light is bent as it passes from air into a gem |
|
|
Term
|
Definition
| resistance of a stone to scratching; usually greater hardness = greater value |
|
|
Term
|
Definition
| appearance of light as it reflects off the surface of the gem |
|
|
Term
|
Definition
| a solid having a regular internal arrangement of atoms/ions and flat, geometrically arranged outer surfaces |
|
|
Term
|
Definition
| mineral, gas or liquid contained in gem |
|
|
Term
|
Definition
| color of a material when powdered; most streaks are white |
|
|
Term
|
Definition
| weight of gem relative to water |
|
|
Term
|
Definition
| weight of gem relative to water |
|
|
Term
|
Definition
| has no set crystal system or flat faces |
|
|
Term
|
Definition
| made in laboratory; have same chemical, physical and optical properties |
|
|
Term
|
Definition
| imitations that mimic the physical and optical properties of diamonds |
|
|
Term
|
Definition
| igneous rock bodies where crystals commonly grow to large size |
|
|
Term
|
Definition
| angle at which total internal reflection is achieved |
|
|
Term
|
Definition
| solids having the same chemical composition but different crystal structures |
|
|
Term
|
Definition
| ultramafic rock in which diamonds are found |
|
|
Term
|
Definition
| coloration of a stone that arises from its internal chemical composition |
|
|
Term
|
Definition
| structural imperfections in crystals that cause colors by the selective absorption of light (radioactive decay, UV radiation) |
|
|
Term
|
Definition
| colors created optically by light reflecting from inclusions |
|
|
Term
|
Definition
| bluish-white glow like a full moon |
|
|
Term
|
Definition
| glittery effect caused by light reflecting off small plates of a mineral within the main mass of a stone |
|
|
Term
|
Definition
| a type of iridescence expressed in pearls |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| alluvial deposits yielding metal flakes or nuggets |
|
|
Term
|
Definition
| a number of materials that are not usually thought of as gemstones |
|
|
Term
|
Definition
| variously shaped pieces of natural glass, often elongated, that apparently have an origin either as meteorites or as terrestrial rock |
|
|
Term
|
Definition
| process of secreting mineralized skeletons |
|
|
Term
|
Definition
| forms when a parasite or foreign matter enters the body of a pearl-forming mollusk |
|
|
Term
|
Definition
| forms as a result of humans placing an irritant inside a mollusk shell |
|
|
Term
|
Definition
| begins when a bead nucleus and a piece of mantle tissue are inserted into a pearl oyster (bead nucleation) |
|
|
Term
| freshwater cultured pearl |
|
Definition
| begins when a piece of mantle tissue is inserted into a freshwater mussel (tissue nucleation) |
|
|
Term
|
Definition
| coating made from fish scales to resemble pearls |
|
|
Term
|
Definition
| in shell and pearl, the nacreous layer |
|
|
Term
|
Definition
| fossil resin which is usually millions of years old and well polymerized and cross-linked |
|
|
Term
|
Definition
| subfossil resin which is rarely more than a few thousand years old, and is poorly polymerized and cross-linked |
|
|
Term
|
Definition
|
|
Term
|
Definition
| it can occur in nature in the pure state, uncombined with any other element to form a compound |
|
|
Term
|
Definition
| crystals become cloudy due to radioactive decay |
|
|
Term
|
Definition
| mixture of metals to increase hardness and durability |
|
|
Term
|
Definition
| when gold is electroplated over another metal (sterling silver) |
|
|
Term
|
Definition
| alternating layers of aragonite and conchiolin |
|
|
Term
|
Definition
| pearls having unusual size and shape |
|
|
Term
|
Definition
| synthetic black glass simulated as jet |
|
|
Term
|
Definition
| synonym for petrified wood |
|
|
Term
|
Definition
| distinctive series of wavy, intersecting lines that is found in ivory |
|
|
Term
|
Definition
| poorly crystallized diamond; black, gray, brown; most common form of industrial grade diamond |
|
|
Term
|
Definition
| spherical aggregates of many small diamond crystals |
|
|
Term
|
Definition
| opaque diamond that is tough and compact; may be a type of meteorite |
|
|
Term
|
Definition
| grow attached to the inside of a saltwater or freshwater mollusk shell, resulting in one side being flat and lacking nacre |
|
|
Term
|
Definition
| made by removing a blistered pearl from the shell, removing the nucleus and filling it with epoxy or a bead, and then gluing the pearl to a mother-of-pearl backing |
|
|
Term
|
Definition
| remains or other evidence of ancient organisms |
|
|
Term
|
Definition
|
|
