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Glossary

Asscher Cut

A square emerald cut with wide corners, a high crown, and a deep pavilion (see Diamond Shapes).

Baguette

A small, rectangular to square step-cut diamond; sometimes tapered (see Diamond Shapes)

Bezel Setting

A Thin strip of metal encircling a stone to secure it in a setting.

Black Diamond

A very dark diamond which appears black and opaque due to numerous inclusions which block the transmission of light.

Blemish

A Term used by GIA to describe a defect on the surface of a polished diamond.

Brilliance

The intensity of the internal and external reflections of light from the crown of a polished diamond.

Carat Weight

The weight of a diamond expressed in metric carats (See Diamond Characteristics).

Champagne Diamond

A light brown to dark brown coloured diamond, also called a cognac diamond.

Channel Setting

The setting style in which diamonds are set between two parallel metal walls with no metal between them.

Clarity

A diamond's relative freedom from inclusions and blemishes (see diamond characteristics).

Claw Setting

A set of narrow metal supports also known as prongs to hold a diamond.

Cognac Diamond

A light brown to dark brown coloured diamond, also called a champagne diamond.

Colour Grade

The relative position of a diamond's body occur on a colourless- to-light-yellow scale (See Diamond Characteristics).

Crown

The part of the diamond above the girdle, i.e. the top of the diamond.

Crown Height

The distance between the girdle and the table of a diamond.

Crown Height Percentage

The distance between the girdle and the table of a diamond, expressed as a percentage of the average girdle diameter.

Culet

A small facet on the point of the pavilion of a brilliant cut diamond, i.e. the point at the bottom of the diamond.

Cushion Cut

A modified brilliant cut diamond with curved sides and rounded corners (see Diamond Shapes).

Cut

The relative proportions and finish of a polished diamond (see Diamond Characteristics)

Depth

The dimension of a diamond from the table to the culet of a diamond.

Diameter

The distance from one edge of the girdle on a diamond to the opposite edge.

Diamond

A mineral composed of carbon crystallised at extremely high pressures and temperatures.

Diamond Certificate

A report written by a grading laboratory, such as the Gemological Institute of America (see Diamond Certification).

Emerald Cut

A rectangular step cut with diagonally cut corners (see Diamond Shapes).

Facet

A flat polished surface on a finished diamond.

Finish

The quality of a diamond's polish, the condition of the girdle and the precision of the cut.

Fire

The rainbow prism of light that is reflected from a polished diamond, technically known as "dispersion". The better a diamond is cut; the more fire is emitted from the diamond.

FL

Flawless, the clarity grade applied to diamonds with no internal or external blemishes or inclusions.

Fluorescence

The emission of visible light by a diamond when stimulated by high energy light such as UV light. Fluorescence rarely affects a diamond's sparkle and brilliance, and in warmer or lower coloured diamonds, fluorescence makes them look whiter or more colourless.

Four C's

The four characteristics which determine the quality and value of a diamond: cut, colour, clarity and carat weight (see Diamond Characteristics).

Gemological Institute of America (GIA)

A non-profit educational institution, established in 1931 to serve the diamond industry and the public. The grading scales developed by the GIA have become the standards for diamond grading all over the world.

Girdle

A narrow band which surrounds the edge of a diamond separating the crown (top) from the pavilion (bottom).

Grain Setting

The setting style in which small diamonds are held in place with small beads of metal.

Hardness

Diamond's resistance to scratching and abrasion.

Heart Shape

Modified brilliant cut in the shape of a heart (see Diamond Shapes).

Internally Flawless

The clarity grade applied to diamonds with no internal blemishes or inclusions.

Inclusion

An internal characteristic of a diamond otherwise referred to as a blemish.

Laser Inscription

An identifying number or message engraved on a diamond (usually on the girdle) using a laser.

Marquise Cut

A modified brilliant cut boat-shaped diamond with curved sides and pointed ends (see Diamond Shapes).

Near-Colourless

The term used to describe diamonds which appear colourless when viewed from above.

Pave Setting

The setting style in which many small gemstones are placed close together.

Pavilion

The portion of the polished diamond below the girdle, ie. bottom section of the diamond.

Pavilion Depth

The distance between the girdle and the culet of a diamond.

Pavilion Depth Percentage

The distance between the girdle and the culet of a diamond, expressed as a percentage of the average girdle diameter on round brilliant cuts, and as a percentage of the width on non-round shaped diamonds.

Pear Shape

A modified brilliant cut with one rounded end and one pointed end which has a pear-shaped girdle outline when viewed from above (see Diamond Shapes).

Polish

The condition of the facet surfaces on a polished diamond.

Princess Cut

A square modified brilliant cut usually with 57 facets (see Diamond Shapes).

Proportions

The relative dimensions and angles of a polished diamond and the relationship between them.

Quality

The relative excellence of a diamond's cut, colour and clarity.

Radiant Cut

A square or rectangular modified brilliant cut with the corners trimmed (see Diamond Shapes).

Reflection

The bouncing back of light when reflected from a polished diamond's surface.

Round Brilliant Cut

The standard round cut diamond with a circular girdle and 57 or 58 facets as it may or may not have a culet (see Diamond Shapes).

Scintillation

The sparkles and flashes that a diamond produces when it is tilted or rotated in the light giving a diamond its beauty.

Shape

The girdle outline of a diamond when viewed from above.

SI

Slightly included, clarity grading for diamonds (see Diamond Characteristics)

Solitaire

A ring with a single diamond.

Stone

A diamond industry term for any polished diamond.

Symmetry

The grading term for the exactness of shape and placement of facets.

Table

The large facet in the centre of the crown of a polished diamond.

Table Diameter

The distance between any two opposing sides of the table on a round brilliant cut diamond.

Table Percentage

For round brilliant cuts, the size of the table expressed as a percentage of the average girdle diameter.

Tapered Baguette

A modification of the rectangular baguette in which one end is narrower than the other.

Total Depth Percentage

The depth from the table to the culet, expressed as a percentage of the average girdle diameter of a round brilliant cut, and as a percentage of the girdle width on non-round diamonds.

Trilliant Cut

A modified brilliant cut with a triangular girdle outline when viewed from above.

VS

Very Slightly Included, clarity grading for diamonds (see Diamond Characteristics).

VVS

Very Very Slightly Included, clarity grading for diamonds (see Diamond Characteristics).