Diamond Fire – Light game in the stone caused by refraction of white light to the colors it contains.
Brilliance & Luster – White light that returns to the eye of the viewer from inside the stone or its surface.
Briefca – An envelope used to store diamonds.
Gadolinium Gallium Garnet – One of the diamond replicas created in the lab, the final product is lusterless, lacks fire and is heavier than a real diamond.
Gletz – A crack in the diamond. The word was taken from the Dutch language meaning – feather. Indeed, some of the cracks look like feathers.Girdle – The external scope of the polished stone. The part is separating the crown and the
Top Silver Cape – A color range according to the English rating system, a parallel to J color in the American method.
Top Light Brown – Diamonds with a slight brown toning instead of yellow. It is parallel to the H and I ranks.
Yttrium Aluminum Garnet (YAG) – One of the diamond replicas created in the lab, the final product is lusterless, lacks fire and is heavier than a real diamond.
Crown – The diamond’s part from the girdle and up.
Hearts & Arrows – An optical phenomenon observed in a stone with ideal proportions and perfect symmetry.
Commercial White – A term used to describe color ranks by merchants. A parallel to I and J ranks of the GIA.
Top White – A term used to describe color ranks by merchants. A parallel to the best rankings of the GIA (D E F).
Loupe – A magnifying glass used to examine the diamonds. The usual magnifying: x10 to test cleanliness, x7 to examine polishing and x6 for sorting. It is recommended that the loupe will be the kind that corrects color distortion and spherical distortion.
Light Brown – Diamond with a brown toning, a parallel to the J and K rankings of the GIA.
Moissanite – One of the diamond replicas that emerged in the market in a colorless version in 1998. The chemical compound of the Moissanite is silicon carbide and it was created at the end of the 18th century, and got the name Carborundum. It was used for producing polishing tools. The Moissanite is almost colorless and it has a DR double refraction and is 10% lighter than a diamond. It has a hardness rank of 9.25 (a diamond has a 10) but has round facet meetings. The stone has a thermal conductivity, and as such, some of the diamond identification devices might indicate it is a diamond.Fracture
Treatment – A kind of treatment that allows improvement of the diamond’s appearance in case of open cracks by the installation of a foreign substance (Silicon). The treatment is resistant to daily conditions but heating the stone to a high temperature or deep boiling will restore the condition. Every treatment must be reported.
Scintillation – White light that returns to the eye of the viewer due to movement of the source of light or movement of the stone.
Point – A weight unit equivalent to 0.01 carat.
Silver Cape – A color range according to the English rating system, a parallel to K and L color in the American method.Culet- The flat polished face that is parallel to the table at the meeting point of the pavilions. Its purpose is to minimize the damage to the fragile point tip.
Fish eye – A phenomenon observed in stones with a flat pavilion. Creates a reflection of the girdle inside the stone. Observable by eye in the direction of the crown.
Fancy cut – A term used to describe a diamond that is not round cut.
Pavilion – The bottom part of the diamond, from the girdle and down.
The Four C’s – The four criteria to estimate the value of a diamond – carat, cut, color and clarity.
Pique – Small bright or dark inclusions inside a diamond. This term is used when sorting polished diamonds by the clarity that matches the GIA’s I ranking.
Facet – A polished plain in a diamond.Proportion – Size of the stone, in percentage, compared to the diameter. Correct proportions create a full light reflection, which grants a diamond its typical light games.
HTHP – A kind of treatment of diamonds used to change their color. In the past radioactive isotopes were used to change the interlace structure observed by the eye as a different color. As of today, with advanced technology, you can change and improve the color of diamond and in some cases make them colorless. This process uses high temperatures and high pressure.
Fancy color – Diamonds with special/rare colors.
Collection – Elite quality merchandise. Quality color sorting by the highest color rankings. Used mostly to describe color in small stones which can’t be ranked by
color separately, and when the stones are in a package.
KM – A new drilling process in diamonds in which the drilling “pipe” does not remain. Instead, they make the existing crack in the diamond open and reach the surface and thus allowing to whiten it in a deep boiling process.
Cape – A name used to describe color in stone with obvious yellow toning observed from the crown.
Rapaport Diamond Report – Polished diamond price list issued by Martin Rapaport’s company, a diamond broker from the USA. The price list presents the recommended standard for the different sortings of the diamonds, although in
reality the prices are determined by the power of the market, supply and demand.
Table – The octagon plain polished in the crown.