| Abrasion |
Tiny
nicks along facet junctions, producing white fuzzy lines instead of sharp
crisp facet edges. |
| Baguette |
A
step cut in the shape of a small rectangular stone. May be tapered at one end. |
| Bezel
|
A
facet on the Crown, or upper part of the Diamond above the Girdle. |
| Blemish |
Surface
imperfection external to the Diamond. |
| Bruise |
An
inclusion consisting of surface crumbling, often accompanied by tiny,
root like feathers . |
| Carat Weight |
The
metric carat, which equals 0.200 gram, is the standard unit of weight
for diamonds and most other gems. If other factors are equal, the more
a stone weighs, the more valuable it will be. |
| Cavity |
An
inclusion consisting of a large or deep opening in the stone. |
| Certificate |
Laminated
document by a gemological institute to describe a Diamond's characteristics. |
| Chip |
A
tiny piece missing, caused by normal wear and tear, or by cutting. |
| Clarity |
A
stone'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 stones are most valuable. |
| Cloud |
A
group of tiny white inclusions which result in a milky or cloudy appearance. |
| Color |
Grading
color in the normal range involves deciding how closely a stone'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 stone. 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 stone; the more successful the cutter is in balancing
these considerations, the more valuable the stone will be. |
| CZ |
Cubic
zirconium. A widely used simulant, an imitation for a natural diamond.
CZ, although easy detectable by its 80% higher weight than a diamond of
the same prortions or by thermal conductivity testing, does often fool
lay persons. |
| Facet |
Angled cut surface,
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 stone. |
| 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. |
| GIA |
Gemological
Institute of America. Reliable diamond grading reports. Diamond research. |
| Girdle |
The
outer edge or the widest part of the diamond forming a band around the
stone. |
| 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. |
| Hue |
Pure,
spectral (prismatic) color. Hues include gradations and mixtures of red,
organdy, yellow, green, blue, violet and purple. |
| 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. |
| Laser
Indentification |
Microscopical
small inscription by a laser on a diamond for indentification. Can be
the diamond certificate number, a message, brandname and number or otherwise.
|
| Loupe |
Magnifying
glass usually of 10X. |
| Melee |
Small
Diamonds under .20 carat. Usually .10ct diamonds. |
| 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 cutter attempting to maximize the
weight retention of the rough Diamond. Frequently noticed on .00ct Diamonds
in order to maintain a commercial interesting
weight i.e. 2.00ct . |
| 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. |
| Pit |
A
tiny opening, often looking like a white dot. |
| Point |
100th
of a carat. |
| 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. |
| Scratch |
A
linear indentation normally seen as a fine white line, curved or straight. |
| Surface
Graining |
Surface
indication of structural irregularity. May resemble faint facet junction
lines, or cause a grooved or wavy surface, often cross facet junctions. |
| 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 by extreme
pressure and heat, ... |
| Zirconium, Zirconia |
Zr
is a natural occurring metal. Synthesized in crystal form, cubic zirconia CZ,
as simulant. |
