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Basic Terminology
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Basic Terminology Natural – Gemstone formed by nature. Natural with Color Enhancement – Gemstone formed by nature that has had its color altered by human
intervention. Natural with Clarity Enhancement – Gemstone formed by nature that has had its clarity altered by
human intervention. Synthetic – Man-made diamond, produced either by subjecting carbon-bearing material such as graphite
to high temperature and pressure (HTHP) or by chemical vapor deposition (CVP). Imitation – a man made material that has no natural counter part that is produced to imitate a natural
gemstone. Examples would be CZ, Glass or Plastic Simulant – Any natural material that is not the known gemstone used to simulate a known stone. An
example would be using a Natural White Sapphire as a substitute for a Diamond. Treatment / Enhancements – Any post-recovery process which alters the appearance, especially the
color or clarity, of a natural gemstone. Types of Treatment: Coating, fracture filling, irradiation, heating (annealing),
and lasering. Rough – Diamond of either cuttable or industrial quality, as it is recovered from the earth, prior
to undergoing any manufacturing process. Facet - flat, polished surface on a finished gemstone. Step Cut – Cutting style in which long, narrow, four-sided facets are arranged in rows parallel to
the girdle on both the crown and pavilion. Ideal – A term applied to Round Brilliant Diamonds only. Diamonds fashioned to proportions and facet
angles which yield the maximum brilliance consistent with high dispersion. The proportions are confirmed mathematically by
Marcel Tolkowshy and are utilized by the American Gemological Society (AGS) |
