GLOSSARY OF TERMS

Blemish: A specific type of clarity that takes place on the surface of a diamond. Some blemishes are intrinsic to the initial forming of the rough diamond. However, most are the result of the environment the diamond has encountered since it s detection.

Brightness: The amount of white light reflected to the viewer of the diamond

Brilliance: The luster that is emitted from the very heart of a diamond. Brilliance is made when light enters through the table, reaches the pavilion facets, and is then reflected back out through the table, where the light is most visible to your eye. GCAL’s Optical Brilliance Analysis directly examines the light return of diamonds. First, a digital image of the diamond is recorded in a special lighting environment, and secondly, the image is processed in a proprietary computer program that calculates the percentage of light returned to the viewer and the amount of light loss.

Carat: The unit of weight by which a diamond is measured. One carat equals 200 milligrams, or 0.2 grams. The word comes from the carob bean, whose stable weight was used in times past to measure gemstones.

Cleavage: The inclination of crystalline minerals, such as diamond, to divide in one or more directions either along or parallel to certain planes, when struck by a blow. Cleavage is one of the two methods used by diamond cutters to split rough diamond crystals in preparation for the cutting process (sawing is the other method).

Clouds: A combination of a number of extremely tiny pinpoints, which are often, but not always, too small to be distinguished from one another even under magnification. Under a microscope, this grouping often looks like a soft transparent cloud inside the diamond. Clouds can range from VVS1 to as low as I3.

Color Grading: An arrangement of grading diamond colors based on their colorlessness (for white diamonds) or their spectral hue, depth of color and purity of color (for fancy color diamonds). For white diamonds, a grading system is used which runs from D (totally colorless) to Z (light yellow). Contrast – The light and dark patterns noticed when observing a faceted diamond. It can be positive or negative in its optical effect.

Crown: The higher or upper piece of a cut gemstone, which is present right above the girdle. The crown consists of a table facet bounded by either star and bezel facets (on round diamonds and most fancy cuts) or concentric rows of facets reaching from the table to the girdle (on emerald cuts and other step cuts).

Crown angle: The angle at which a diamond's bezel facets interconnect with the girdle plane. This gentle incline of the facets that enclose the table is what helps to create the scattering, or fire, in a diamond. The crown angle also helps to enhance the brilliance of a diamond.

Culet: A small flat facet that diamond cutters sometimes add at the bottom of a diamond's marquee. Its function is to protect the tip of the diamond’s marquee from being chipped or scratched. Once a diamond is set in jewelry, though, the setting itself generally provides the pavilion with sufficient protection from impact or wear. Large or extremely large culets were common in diamonds cut in the 19th and early part of the 20th century, such as the Old European or Old Mine Cut.

Cut: This refers to the proportion, finish and light performance of a polished diamond. As one of "the Four Cs" of diamond value, it is the only man-made involvement in a diamond's beauty and value.

Diamond: A crystal made up of 99.95% pure carbon atoms arranged in an isometric, or cubic, crystal assembly. It is this unique assembly of the carbon atoms that makes a diamond look and behave differently from other pure carbon minerals such as graphite.

Dispersion: The play of small flashes of color across the surface of the diamond as it is tilted. Dispersion is sometimes also called "fire." Dispersion is caused when light hits the small, angled facets (bezel and star facets) set around the crown of the diamond; these varying angles cause the white light to separate into its component spectral colors (for example, red, blue and green). This play of color should not be confused with a diamond's natural body color (normally white, though sometimes yellow, brown, pink or blue in the case of fancy color diamonds) which is uniform throughout the entire diamond and is constant, regardless of whether it is being tilted or not.

Eye-Clean: Lingo used in the jewelry industry to describe a diamond with no blemishes or inclusions that are visible to the naked eye

Facet: The smooth, flat faces on the surface of a diamond. They allow light to both enter a diamond and reflect off its surface at different angles, creating the wonderful play of color and light for which diamonds are famous.

Fancy Shape: Any diamond shape other than round, such as per shape, princess, marquise, and others (see listing under Diamond Shapes).

Feathers: These are small fractures in a diamond. They are usually caused by the incredible stress that the diamond suffered while it was growing underground. In some cases the feather both begins and ends within the diamond's surface and, in other cases, the feather begins inside the diamond and extends to the surface. When viewed under magnification, some feathers are transparent and others have a light white appearance to them. The term "feather" comes from the fact that, under magnification, these fractures often seem to have an unclear, feathery shape to them. While the idea of buying a diamond with "fractures" may sound scary, the reality is that, with normal wear and care, most feathers pose no risk to the diamond's stability.

Finish: This term refers to the character passed on to a diamond by the skill of the diamond cutter. The term "finish" covers every aspect of a diamond's final look that is not a result of the diamond's inherent nature. The execution of the diamond's design, the precision of its cutting details, and the quality of its polish all contribute to a diamond’s finish. If you examine a diamond's grading certificate or report, you will see its finish graded according to two separate categories: polish and symmetry.

Fluorescence: An effect that is seen in some gem-quality diamonds when they are exposed to long-wave ultraviolet light (such as the lighting frequently seen in dance clubs). Under most lighting conditions, this fluorescence is not detectable to the eye. However, if a diamond is naturally fluorescent, it will emit a soft colored glow when held under an ultraviolet lamp or "black light." Fluorescence is not dangerous to the diamond or to the wearer; it is an exclusive and charming quality that occurs naturally in a number of gems and minerals.

Girdle: The exterior edge, or outline, of the diamond's shape. The girdle is not graded, but rather it is described by its appearance at its thinnest and thickest points. The descriptions of girdle thickness range as follows: extremely thin; very thin; thin; medium; slightly thick; thick; very thick; extremely thick.

Inclusion: A clarity characteristic found within a diamond. Most inclusions were created when the gem first formed in the earth.

Leakage: Areas that do not return light.

Light Performance: An analysis of brightness, dispersion, leakage, and contrast.

Pavé: A style of jewelry setting in which many small diamonds are mounted close together to create a shiny diamond crust that covers the whole piece of jewelry and obscures the metal under it.

Pavilion: The lower portion of the diamond, below the girdle.

Point: A unit of measurement used to describe the weight of diamonds. One point is equivalent to one-hundredth of a carat.

Polish: Refers to any blemishes on the surface of the diamond which are not significant enough to affect the clarity grade of the diamond. Examples of blemishes that might be considered as 'polish' characteristics are faint polishing lines and small surface nicks or scratches. Polish is regarded as an indicator of the quality of a diamond's cut; it is graded as Ideal, Excellent, Very Good, Good, Fair or Poor.

Semi-mount: A jewelry setting that has the side stones already mounted, but which contains an empty set of prongs which are intended to mount a diamond center stone that the customer selects separately.

Single-cut: A very small round diamond with only 16 or 17 facets, instead of the normal 57 or 58 facets of a full-cut round brilliant. Single cuts are occasionally used for pavé jewelry and other jewelry that utilizes numerous small diamonds set closely together.

Symmetry: GCAL’s Optical Symmetry Analysis shows the colored areas of the symmetry image as a visual representation of the alignment of facets and the consistency of angles. It is a direct assessment of the precision of the cut and craftsmanship. Symmetry plays an important role in the beauty of any object. The small variations can include 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 either: Ideal, Excellent, Very Good, Good, Fair or Poor.

Table: The flat facet on the top of the diamond. It is the largest facet on a cut diamond.

Tilt: The point at which the girdle reflects under the table facet.