| Term |
Diamond Glossary by rab for Paul Van den Eynde |
| Abrasion |
Tiny nicks along facet junctions, producing white fuzzy lines instead of sharp crisp facet edges. |
| Antwerp | Diamond center of the world, 2nd largest port of Europe on the river Scheldt, Belgium. Home town of Van den Eynde and fun evenings. |
| Baguette |
A step cut in the shape of a small rectangular diamond. May be tapered at one end. |
| Bearded girdle, or Bearding |
Tiny, numerous, hairlike fractures extending into the diamond. |
| Bezel |
A facet on the Crown, or upper part of the Diamond above the Girdle. |
| Blemish |
Surface imperfection external to the Diamond. |
| Bort |
Industrial grade diamonds |
| Bow Tie Effect |
An effect caused by a shadowy area visible in some fancy shapes, caused by light leaking out the bottom of the Diamond. |
| Bruise |
An inclusion consisting of surface crumbling, often accompanied by tiny, root like feathers . |
| Burned Facet |
This facet may appear whitish, or burnt, as a result of the cutter polishing the facet "against the grain". |
| Carat Weight |
The metric carat, which equals 2 milligram, is the standard unit of weight for diamonds and most other gems. If other factors
are equal, the more a diamond weighs, the more valuable it will be. |
| Cavity |
An inclusion consisting of a large or deep opening in the diamond. |
| Certificate | Laminated document by a gemological institute to describe a Diamond's characteristics. |
| CGL | Central Gem Laboratory, established in 1970 in Tokyo. Diamond grading and Identification. Grading of excellent cut and 'Hearts and Arrows'. Overseas office in cooperation with the HRD in Antwerp since 1992. |
| Chip |
A tiny piece missing, caused by normal wear and tear, or by cutting. |
| Clarity |
A diamond's relative position on a flawless to imperfect scale. Clarity characteristics are classified as inclusions (internal) or
blemishes (external). The size, number, position, nature, and color or relief of characteristics determine the clarity grade. Very
few diamonds are flawless, that means, show no inclusions or blemishes when examined by a skilled grader under 10X
magnification. If other factors are equal, flawless diamonds are most valuable. |
| Cloud |
A group of tiny white inclusions which result in a milky or cloudy appearance. |
| Coated Diamond |
A diamond colored by a surface coating which masks the true body color; the coating may be extensive (entire pavilion, for
example), but is more often limited to one or two pavilion facets or a spot on the girdle. |
| Color |
Grading color in the normal range involves deciding how closely a diamond's body color approaches colorlessness. Most
diamonds have at least a trace of yellow or brown body color. With the exception of some natural fancy colors, such as blue,
pink, purple, or red, the colorless grade is the most valuable. |
| Crown |
The upper part of the diamond above the girdle. Consists of a large flat area on top called a table, and several facets below it. |
| Culet |
The smallest facet at the bottom of the diamond. |
| Cut |
The proportions and finish of a polished diamond (also called make). Cut can also mean shape, as in emerald cut or marquise
cut. Proportions are the size and angle relationships between the facets and different parts of the diamond. Finish includes polish
and details of facet shape and placement. Cut affects both the weight yield from rough and the optical efficiency of the
polished diamond; the more successful the cutter is in balancing these considerations, the more valuable the diamond will be. |
| CZ | Cubic zirconia. A widely used simulant, an imitation for a natural diamond. |
| Emerald cut |
A step cut, usually rectangular. |
| Excellent cut |
A GIA and HRD-CGL grade for excellent cut and polish of brilliants. In Antwerp manufactured at Fr. Van den Eynde & Zn |
| Extra Facet |
A facet placed without regard for symmetry and not required by the cutting style. |
| Facet |
Plane, polished surface of a diamond. |
| Faceted Girdle |
Sometimes cutters polish the girdle into 32 facets.
|
| Fancy Diamond |
A diamond with an attractive natural body color other than light yellow or light brown. |
| Feather |
A separation or break due to either cleavage or fracture, often white and feathery in appearance. |
| Flaw |
An imperfection of a diamond. |
| Fluorescence | Mostly blueish glow of a Diamond in high ultraviolet lighting conditions. Ratings: none, faint, slight, medium, strong blue. Strong blue fluorescence may cause the diamond to appear oily in daylight. |
| Fracture |
A crack on the diamond's surface. |
| GGG | Gadolinium
Gallium Garnet, a modern imitation of a natural diamond. |
| GIA | Gemological Institute of America. Reliable diamond certification. Diamond research. |
| Girdle |
The outer edge or the widest part of the diamond forming a band around the diamond. |
| Grain Center |
A small area of concentrated crystal structure distortion, usually associated with pinpoints. |
| Hardness |
Mineral's resistance to scratching on a smooth surface. Mohs scale of relative hardness consists of 10 minerals, each
scratching all those below it in scale and being scratched by all those above it. |
| HRD | Hoge Raad voor Diamant. An independent non profit institute in Antwerp for the Diamond industry. Reliable impartial Diamond certification controlled by Belgian state authorities. |
| Hue |
Pure, spectral (prismatic) color. Hues include gradations and mixtures of red, organdy, yellow, green, blue, violet and purple. |
| Imitation | See simulants |
| Included Crystal |
A mineral crystal contained in a diamond. |
| Inclusion |
Imperfection internal to the Diamond. |
| Internal Graining |
Internal indications of irregular crystal growth. May appear milky, like faint lines or streaks, or may be colored or reflective. |
| Irradiated diamond |
A diamond which has been exposed to radiation. |
| Knot |
An included diamond crystal which reaches the surface of a polished diamond. |
| Laser Drill Hole |
A tiny tube made by a laser. The surface opening may resemble a pit, while the tube usually looks needle like. May be noticeable on treated Diamonds. |
| Loupe |
Magnifying glass usually of 10X. |
| Melee |
Small Diamonds under .20 carat, usually .10ct. Blanka Diamonds specialization: brilliants from 200/ct to 5/ct. |
| Mohs scale |
The ten point scale of mineral hardness, keyed arbitrarily to the minerals: talc, gypsum, calcite, fluorite, apatite, orthoclase,
quartz, topaz, corundum, and diamond. |
| Natural |
Part of the rough diamond remaining on the diamond, having survived the cutting process. This is usually the sign of a good
cutter attempting to maximize the weight retention of the rough Diamond. |
| Needle |
A long, thin included crystal which looks like a tiny rod. |
| Nick |
A notch near the girdle or a facet edge. |
| Off Make |
A poorly proportioned Diamond. |
| Old European Cut |
Early round cut similar to the Round Brilliant Cut, but carrying a very small table and heavy crown. Not as popular today
because it does not return the same brilliance as the modern brilliant. |
| Pavilion |
The bottom part of the Diamond, below the girdle. |
| Pinpoints |
Miniscule spots internal to a Diamond. A cluster of pinpoints can form a cloud. |
| Moisannite | Created moissanite produced by Charles & Colvard, a simulant. Its double refraction is one of the few differences with a diamond. |
| Pit |
A tiny opening, often looking like a white dot. |
| Point |
100th of a carat. Blanka Diamonds delivers from 0.5 points to 20 points brilliants. |
| Polish Lines |
Tiny parallel lines left by polishing. Fine parallel ridges confined to a single facet, caused by crystal structure irregularities, or
tiny parallel polished grooves produced by irregularities in the scape surface. |
| Polish Mark |
Surface clouding caused by excessive heat (also called burn mark, or burned facet), or uneven polished surface resulting from
structural irregularities. |
| Rough Girdle |
A grainy or pitted girdle surface, often with nicks. |
| Round Brilliant cut |
The most common cut usually containing 58 facets. Also the most brilliant cut, in terms of most efficient use of light to increase
brilliance and fire, hence the name. See also 'Hearts and Arrows' |
| Saturation |
A color's position on a neutral to vivid scale. |
| Scratch |
A linear indentation normally seen as a fine white line, curved or straight. |
| Simulant | Also called: Imitation. Any diamond like
material, either natural or artificial, which is marketed as
look-alike for a natural diamond. i.e. Glass, - zirconium, YAG, GGG, moissanite etc. |
| Spread diamond |
A Diamond with a large table and a thin crown height. |
| Surface Graining |
Surface indication of structural irregularity. May resemble faint facet junction lines, or cause a grooved or wavy surface, often
cross facet junctions. |
| Tone |
A color's position on a colorless-to-black scale. |
| Treated Diamond: |
Fancy color treatment: A diamond with a bodycolor induced by some form of artificial irradiation, often in conjunction with controlled heating (known as annealing). Other possible treatments of diamonds are: coating, fracture filling, spot bleaching by laser, electromagnetic conduction, whitening . |
| Twinning Wisp |
A cloudy area produced by crystal structure distortion, usually associated with twinning planes. |
| YAG | Yttrium Aluminum Garnet, a modern simulant, so an imitation for a natural diamond |
| Zirconium | Zr is a natural occurring metal. Synthesized in crystal form, cubic zirconia CZ, as simulant. |
