Glossary of Terms

Abrasion - These are tiny nicks along facet junctions. So instead of sharp crisp facet edges you get fuzzy white lines.

AGS - Stands for American Gem Society. This is an educational institution for gemological studies. The AGS Labs were created primarily to develop and promote universally accepted standards for grading cut. Bezel - Is the facet on the Crown, or upper part of the diamond situated above the Girdle.

Blemish - Is a clarity characteristic that occurs on the surface of a diamond. It therefore has an external imperfection.

Bow Tie Effect - When light leaks out the bottom of the diamond it results in an effect that causes a visible shadowy area.

Brilliance - The effect that makes Diamonds unique and special. It is the brightness that emanates from the very heart of a diamond. Whilst it’s true that other Gemstones do also display brilliance, none match the power and effect of a diamond's light-reflecting power.

Bruise - An inclusion consisting of surface crumbling, often accompanied by tiny, root like feather effect.

Carat Weight - The standard unit of weight for diamonds, the metric carat, equals 2 milligrams. If other factors are equal, the more a diamond’s carat weight, the more valuable it will be.

Cavity - An inclusion consisting of a large or deep opening in the diamond.

Certificate - A document issued by a gemological institute to describe a diamond's characteristics but not it’s value.

Chip - A tiny piece missing, caused by normal wear and tear, or by cutting.

Clarity - A scale used to ascertain a diamond's measure of flawlessness to imperfection. Clarity characteristics are classified as inclusions (internal) or blemishes (external). The clarity grade is determined by the diamond’s size, number, position, nature and color. Very few diamonds are flawless, that means, show no inclusions or blemishes. All other factors remaining equal, a flawless diamond will command the highest prices.

Cloud - A group of tiny white inclusions that result in a milky or cloudy effect.

Color - A Colorless diamond is the best. Color grading normally involves deciding how closely a diamond's body color approaches colorlessness. However, most diamonds will have at least a trace of yellow or maybe brown body color.

Crown - The uppermost part of the diamond above the girdle setting. Consisting of a large flat top area, also known as a table, and several facets below it.

Crown Angle - The angle at which a diamond's bezel facets intersect the girdle plane. It is the gentle slope of the facets that surround the table that help create the dispersion of light in a diamond, also known as the fire. When light enters the diamond at the ifferent angles it is broken up into its spectral hues, creating a beautiful play of color inside the diamond. The crown angle also helps to enhance the brilliance of the diamond.

Culet - The bottom of the diamond and hence the smallest facet.

Cut - The proportions and finish of a polished diamond. It can also mean the shape, as for example, in pear cut or Princess cut. The proportions are the angle and size relationships between the facets and different parts of the diamond. The cut of the original rough stone by the jeweler or cutter will affect the final weight of the final polished diamond as well as its optical efficiency. The more skilled the cutter in balancing these considerations, all other factors remaining equal, the higher the final value of the diamond will be.

Depth - Measured in millimetres this is the height of a diamond from the culet to the table..

Depth Percentage - As well as a diamond’s actual depth there is also the depth percentage. This expresses how deep the diamond is in relation to how wide it is.

Emerald Cut - A step cut, usually rectangular.

Excellent Cut - A term used by the top laboratories such as GIA and HRD-CGL to grade the excellence of the cut.

Extra Facet - A facet placed by the cutter without regard for the symmetry of the stone and not required by the relevant cutting style.

Eye-Clean - The term used to describe a diamond with no blemishes or inclusions visible to the naked eye.

Facet - The plane, polished surface of a diamond.

Faceted Girdle - This is where a cutter will sometimes polish the girdle into 32 facets.

Fancy Diamond - A diamond with an attractive natural body color other than Light Yellow or light brown, for example pink.

Feather - Often white and (not surprisingly) feathery in appearance, this is a separation or break due to either fracture or cleavage.

Flaw - Simply an imperfection found in a diamond.

Fluorescence - When viewed under high ultraviolet lighting conditions the diamond will have a mostly blue colored glow. Ratings: none, faint, slight, medium, strong blue. A diamond with a strong blue fluorescence may cause it to appear slightly oily in normal daylight.

racture - A crack on the diamond's surface.

GIA - Stands for Gemological Institute of America. The largest independent institute that provides reliable diamond certificates or grading reports.

Girdle - The widest part or outer edge of the diamond forming a band around the diamond.

Hue - Pure or spectral color. Hues include gradations and mixtures of red, organdy, yellow, green, blue, violet and purple.

ncluded Crystal - A mineral crystal that can be contained in a diamond. Inclusion - An internal imperfection in the Diamond.

Internal Graining - This could be an indication of irregular internal crystal growth. May appear milky or cloudy , collared or reflective.

Loupe - Magnifying glass usually 10Xs strength.

Marquise Cut - A type of fancy shape diamond, which is elongated with points at both end.

Naturals - Small parts of the original rough diamond's surface and therefore blemishes, which are left on the polished diamond usually on or near the girdle. They can be regarded as a sign of a skilled cutter as it portrays the cutter’s ability for creating a beautiful finished stone yet retaining as much of the original crystal's weight as possible. In many cases this does not affect the clarity and is usually undetectable to the naked eye.

Needle - A long, thin included crystal that looks like a tiny rod.

Oval Cut - A type of fancy shaped diamond, which is essentially an elongated version of a round cut.

Pavilion - The bottom part of the Diamond, below the girdle.

Pear Cut - A type of fancy shape diamond that resembles a pear, hence the name, or sometimes known as a teardrop cut.

Pinpoints - Very small spots internal to a diamond. A cluster of pinpoints can form a cloud.

Pit - A tiny opening, often looking like a white dot.

Point - 100th of a carat.

Polish Lines - These are very small parallel lines left by the polishing process.

Polish Mark - This is surface clouding caused by excessive heat (also called a burn mark, or a burned facet), or uneven polished surface resulting from structural
irregularities.

Princess Cut - A type of brilliant fancy cut that can be either square or rectangular in shape.

Radiant Cut - A type of brilliant fancy cut that resembles a square or rectangle in shape with the corners cut off.

Surface Graining - A surface indication of structural irregularity. May resemble faint facet junction lines, or cause a grooved or wavy surface, often-cross facet junctions.

Symmetry - Referring to variations in the diamond's symmetry. The small variations can include a misalignment of facets or facets that fail to point correctly to the girdle. Symmetry is regarded as an indicator of the quality of as diamond's cut; it is graded as Ideal, Excellent, Very Good, Good, Fair or Poor. Any misalignment would be completely undetectable to the naked eye.

Table - The flat facet on the top of the diamond and is the largest facet on a cut diamond.

Table Percentage - The value that represents how the diameter of the table facet compares to the diameter of the entire diamond.

Trillion Cut - A type of brilliant fancy cut that is triangular in shape.