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Setting | Bearding
Facet | Bezel
Setting | Brilliant
Spots | Certificate
Setting | Clarity
Setting | Color
Grading | Color
Angle | Crystal
Depth | Depth
Percentage | Diamond
Cutting | Diamond
Gauge | Dispersion
Reflection | Eye-Clean
a clarity characteristic that occurs on the surface of a diamond.
Though some blemishes are inherent to the original rough diamond,
most are the result of the environment the diamond has encountered
since it was unearthed. (For more information on the most commonly
occurring types of blemishes, please see our detailed discussion,
Diamond Education: Clarity.)
the brightness that emanates from the very heart of a diamond.
The brillance factor makes diamonds unique among all other gemstones.
While other gemstones also display brilliance, none equals a diamond's
light-reflecting power. Brilliance is created primarily 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.
Setting: similar to a channel setting (see below). A bar
setting uses a thin, circular bar of metal to hold the stones in
place on either side, so that each bar has a stone on either side
the term given to the very small feathers (small fractures that
touch the diamond's surface) along the edge of a diamond, usually
appearing at the girdle, or widest part, of the diamond.
Facet: the facet located on the crown, or top portion, of
a diamond. Jewelers call this the 'kite' facet because of its shape.
Setting: holds a diamond in place using a thin band of metal
that surrounds the diamond at its middle, or girdle. Bezel settings
completely or partially surround the stone, depending on the style
and look desired, and provide good protection for the middle and
bottom (pavilion) portions of the diamond.
Cut: a type of round cut that gives the diamond 57 or 58
facets mathematically devised to produce the greatest brilliance.
'Cut' here really refers more to the diamond's shape than its proportions.
of a diamond's weight. A carat is equal to 200 milligrams. (Don't
confuse this Carat with the term 'Karat,' which is a measure of
the purity of gold.) For accuracy, diamonds should be weighed when
they are not mounted in a setting. Each Carat is divided into 100
parts called 'points,' so a 1-carat diamond has 100 points, a ¾
carat has 75 points, etc.
Spots: misnomer used by some people in the jewelry industry
to describe the appearance of certain inclusions in a diamond. 'Carbon
spots' are actually included crystals that have a dark appearance,
rather than a white or transparent appearance, when viewed under
a microscope. In most cases, these dark inclusions are not visible
to the naked eye and do not affect the brilliance of the diamond.
a guarantee by an independent laboratory that the diamond is indeed
of the quality the seller represents. Diamonds are certified by
an independent gemological laboratory with skilled gemologists who
use specialized equipment to measure and evaluate each diamond's
particular characteristics and attributes.
Setting: a setting where two strips of metal (gold, platinum,
etc.) hold the diamond(s) in place at the sides. There is no metal
between the stones. This type of setting protects the girdle area
of the diamond and secures small stones more effectively than a
prong setting. Channel-set diamonds also sit flush with the mounting,
making them less likely to get snagged on other objects, such as
hair or clothing.
measured by a jeweler's loupe (a small magnifying glass used to
view gemstones) under 10-power magnification. The FTC requires all
diamond grading be done under 10-power magnification; any flaws
not detected under this magnification are considered to be non-existent.
the propensity of crystalline minerals, such as diamond,
to split in one or more directions either along or parallel to certain
planes, when struck by a blow. Diamond cutters use one of two processes--cleaving
or sawing--to split rough diamond crystals in preparation for the
a grouping of a number of extremely tiny inclusions too small
to be distinguishable from one another, even under magnification.
But under a microscope, this grouping often looks like a soft transparent
cloud inside the diamond. Clouds cannot be seen with the naked eye,
so usually do not significantly impact a diamond's clarity grade.
Diamond World will not sell any diamond with clouds severe enough
to affect the brilliance of the diamond.
Setting: several stones mounted together in a group, for
a cluster effect. Often several small stones surround a central,
Grading: a system 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
use a grading system which runs from D (totally colorless) to Z
the most important thing to know is that, in general, the less color
a diamond has, the more valuable it is, all other factors being
equal. The less color a diamond has, the more purely it can refract
the light that enters it, making it sparkle with brilliance and
fire. Diamond colors range from colorless to slightly yellow or
brown, to more rare and costly pink, green or blue stones (commonly
referred to as 'fancy' diamonds). Excluding 'fancy' diamonds, the
ideal color for a diamond is colorless, although this is extremely
the upper portion of a cut gemstone, which lies above the
girdle. The crown comprises the table, and the star- bezel- and
upper-girdle facets. On round diamonds and most fancy cuts, the
crown consists of a table facet surrounded by either star and bezel
facets. On emerald cuts and other step cuts, the crown consists
of concentric rows of facets reaching from the table to the girdle.
Angle: a measurement of the angle, in degrees, formed by
the facets of the upper portion, or crown, of the stone. The distance
from the girdle (widest point) to the table (the flat facet at the
top of the stone) determines whether the crown will be thick, thin
or proportionally 'ideal.' Therefore, the higher the crown, the
steeper the crown angle will be; the thinner the crown, the shallower
the crown angle will be. The angles at which the crown and pavilion
facets (those facets below the girdle) are cut directly affects
the diamond's ability to refract light rays, which is what gives
a diamond its remarkable fire and brilliance.
a type of inclusion found in some diamonds. It is simply
a mineral deposit that has been trapped inside the diamond. Crystals
are usually indicated on diamond grading reports. Be aware that
the location and size of the crystal may have a direct bearing on
the diamond's value.
the point on the bottom of a diamond's pavilion. On some diamonds,
the culet is actually formed into a facet; in others, it is formed
into a point. Therefore, round diamonds can have either 58 or 57
facets, depending on whether the culet has been faceted or not.
the only one of the 4Cs that is within a human's control. 'Cut'
refers to the geometric proportions to which a diamond is crafted
(usually by a master diamond cutter with many years of experience).
Once the diamond's shape has been determined, facets are cut. These
facets refract light like a prism and produce the stone's fire and
height of a diamond from the culet to the table. The depth is measured
Percentage: on a diamond grading report, there re two different
measurements of the diamond's depth:
1) the actual depth in millimeters (under 'measurements' at the
top of the report);
2) the depth percentage, which expresses how deep the diamond is
in comparison to how wide it is.
This depth percentage of a diamond is important to its brilliance
and value, but it only tells part of the story. Where that depth
lies is equally important to the diamond's beauty; specifically,
the pavilion should be just deep enough to allow light to 'bounce
around' inside the diamond and reflect out to the eye at the proper
angle. Keep in mind, also, that correct depth percentages vary based
on the diamond's cut. For example, a 75% or 78% depth in a princess
cut diamond would be typical and quite attractive. However, a depth
of even 65% would be unnecessary and even detrimental to a round
pure crystallized carbon, the simplest of all the gemstones.
A diamond begins to crystallize far beneath the earth's surface
among a mixture of liquids, gases, and crystals, called Kimberlite
magma (after the city of Kimberley, South Africa, where diamonds
were found in the 1870's). Since Kimberlite is lighter than surrounding
rocks, it rises as gas from the earth's mantle, creating carrot-shaped
pipes through which diamonds reach the earth's surface. Diamonds
can be from 1 to 3 billion years old-more than two-thirds the age
of the Earth itself. Diamond is also the hardest substance known
to man. In fact, it can only be cut and polished by another diamond.
Despite its hardness, however, it is not indestructible. If a diamond
is struck at the right angle, it can chip or break.
Cutting: the method by which a rough diamond mined from the
earth is shaped into a finished, faceted stone.
First, the diamond often undergoes cleaving or sawing to separate
the rough into smaller, more workable pieces, which will each eventually
become an individual polished gem.
Next, bruting grinds away the edges, providing the outline shape
(for example, heart, oval or round) for the gem.
Faceting is next and is achieved in two steps:
1) during blocking, the table, culet, bezel and pavilion main facets
are cut; afterward,
2) the star, upper girdle and lower girdle facets are added.
Once the fully faceted diamond has been inspected and improved,
it is boiled in hydrochloric and sulfuric acids to remove dust and
oil. The diamond is then considered a finished, polished gem.
Gauge: an instrument used to measure a diamond's length,
width and depth in millimeters.
arranged around the table facet on the crown are several smaller
facets (bezel and star facets) angled downward at varying degrees.
These facets and their angles have been skillfully designed to break
up white light as it hits the surface, separating it into its component
spectral colors (for example, red, blue and green). This rainbow
effect, which appears as a play of small flashes of color across
the surface of the diamond as it is tilted, is what we refer to
as the diamond's dispersion (also called 'fire'). 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). A diamond's natural body color is uniform
throughout the entire diamond and is constant, regardless of whether
it is being tilted or not.
a square or rectangular-shaped diamond with cut corners.
On the crown, there are three concentric rows of facets arranged
around the table; and on the pavilion, there are three concentric
rows arranged around the culet. This type of cut is also known as
a Step Cut because its broad, flat planes resemble stair steps.
Reflection: finely polished diamonds should display a high
degree of external reflection. The finer the polish, the brighter
and more lustrous the diamond will be. External reflection should
not be confused with internal refraction, which refers to the primary
light refraction that causes a diamond's fire and brilliance to
occur inside its facets. External reflection refers to the light
rays that are reflected back to the viewer's eye from the surface
of the stone itself.
an expression that jewelers use to designate a gem whose flaws or
inclusions cannot be detected without a loupe.
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