Gia Colored Stones Exams With All Solutions.

Gia Colored Stones Exams With All Solutions
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Mineral - ANSWER-A natural, inorganic substance with a characteristic chemical composition and usually
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characteristic structure.
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Mixed cut - ANSWER-A cutting style that combines brilliant-cut and step cut facets.
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Abrasions - ANSWER-Tiny nicks and pits caused by wear and damage to a gem's facet edges or culet.
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Absorption spectrum - ANSWER-A pattern of dark vertical lines or bands shown by certain gems when
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viewed through a spectroscope.
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Adularescence - ANSWER-The cloudy bluish white light in a moonstone, caused by scattering of light.
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Agate - ANSWER-Chalcedony with a curved or angular bands or layers that differ in color and transparency .
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,Aggregate - ANSWER-A mass of tiny, randomly oriented crystals.
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Akoya - ANSWER-Common name for the Pinctada fucata oyster and the natural or cultured pearls it
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produces.
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Allochromatic - ANSWER-A gem colored by trace elements in its crystal structure.
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Alluvial deposit - ANSWER-A deposit where gems are eroded from their source rock, then transported away
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from their source and further concentrated.
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Amorphous - ANSWER-Lacking a regular crystal structure.
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Aragonite - ANSWER-A crystalized form of calcium carbonate found in nacre.
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Assembled stone - ANSWER-Two or more separate pieces of material joined to form a unit.
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Asterism - ANSWER-Crossing of chatoyant bands, creating a star in the dome of cabochon.
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Atom - ANSWER-The basic structural unit of all matter.
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Aventurescence - ANSWER-A glittery effect caused by light reflecting from small, flat inclusions within a
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gemstone.
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Background color - ANSWER-An opal's bodycolor, independent of its play-of-color.
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Bead nucleus - ANSWER-A bead used as the core of a cultured pearl, usually made from a freshwater mussel
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shell.
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,Bleaching - ANSWER-A treatment that uses chemicals to lighten or remove color.
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Blemish - ANSWER-Characteristic or irregularity confined to the surface of a polished gemstone.
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Blue Sheen - ANSWER-Trade term for a highly prized, vivid blue adularescence displayed by the finest
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moonstone.
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Bodycolor - ANSWER-A gemstone's basic color, determined by its selective absorption of light.
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Botryoidal - ANSWER-A crystal growth habit with a bumpy appearance similar to a bunch of grapes.
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Boulder opal - ANSWER-Thin layers of precious opal, cut to include matrix.
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Boule - ANSWER-A cylindrical synthetic crystal produced by the flame-fusion process.
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Brilliance - ANSWER-Light that eventually returns to the eye after entering a gem through the crown,
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reflecting off its pavilion facets, and exiting back through the crown.
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Brilliant cut - ANSWER-Cutting style with triangular or kite-shaped facets that radiate from the center
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toward girdle.
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Cabochon - ANSWER-A smoothly rounded polished gem with a domed top and a flat or curved base.
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Calcareous concretion - ANSWER-A non-nacreous natural "pearl".
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Calibrated sizes - ANSWER-Gemstone sizes cut to fit standard mountings.
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, Cameo - ANSWER-A gem carving style in which the design often a women's profile, projects slightly from a
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flat or curved surface.
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Cavity - ANSWER-An opening that extends into a gem from the surface.
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Centipedes - ANSWER-Tiny tension cracks in a moonstone that interfere with adularescence and reduce
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value.
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Ceramic process - ANSWER-A process in which ground powder is heated, sometimes under pressure, to
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produce a fine-grained solid material.
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Certificate of origin - ANSWER-A document that indicates a stone's geographic origin, based on its
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inclusions and trace element chemistry.
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Chalcedony - ANSWER-A cryptocrystalline quartz aggregate.
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Charge transfer - ANSWER-A process where the electrons that selectively absorb light are passed back and
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forth between neighboring impurity ions.
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Chatoyancy - ANSWER-Bands of light in certain gems, caused by reflection of light from many parallel,
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needle-like inclusions or hollow tubes.
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Chemical composition - ANSWER-Kinds and relative quantities of atoms that make up a material.
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Chemical element - ANSWER-A substance that consists of atoms of only one kind.
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Chip - ANSWER-A damaged area on a gem, usually near the girdle.
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