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AGS
American
Gemological Society. Widely respected in the trade, and considered by many the
ultimate authority for cut grading reports.
Blemish
An
exterior imperfection on a diamond, usually a feature of the cutting or
polishing of the stone. A diamond may have blemishes and still have an
"Internally Flawless" (IF) grading. Most blemishes are so small as to have no
affect on the beauty or brilliance of the stone.
Brilliance
Along with life, scintillation, refraction and
dispersion, a word used to describe the ability of a diamond to "sparkle" in
response to the introduction of light.
Carat
Standard unit of
measure for diamonds and other gemstones. One carat is equal to 1/5 of a gram.
There are 100 "points" to the carat (abbreviated ct.)
Clarity
The degree to which a diamond is free from inclusions,
graded on a scale from Flawless (FL) to heavily imperfect (I3). There are 10
grades in total.
Clarity Enhancement
See "drilling" and
"fracture filling". Laboratory reports, such as those offered by Shaftel Diamond
are your best protection against clarity enhanced stones.
Cleavage
An internal feature which runs in the direction of
the grain of the diamond. It sometimes extends to the surface of the diamond, or
is "healed" inside the diamond. A cleavage is sometimes easily visible,
sometimes not. A diamond may be "cleaved," or split in two with a smart,
precisely placed blow to a cleavage.
Cloud
A cluster of
microscopic white or crystalline inclusions or pinpoints inside a diamond.
Usually visible only with back lighting and under high magnification.
Color
For most preferences, the best color is no color or
"colorless". Most diamonds have some lesser or greater degree of yellow or brown
color, sometimes so slight that it is virtually imperceptible. Some rare
diamonds have very intense or exotic colors (pink, blue, green, purple, or even
red) and can be extraordinarily valuable. Colors are designated by letter grades
- "D" for absolutely colorless to "Z" for light yellow, and by verbal
descriptions for the "fancy" colors.
Color
Enhancement
Laboratory processes ranging from a simple coating or
"painting" as it is known in the trade to sophisticated permanent alteration of
the certain trace elements found in the naturally occurring diamond. Laboratory
reports, such as those offered by Shaftel Diamond Company are your best
protection against treated stones.
Culet
The bottom most facet
or point of a diamond. The culet of some diamonds may be so pointed so as not to
be considered a facet at all.
Cut
Cut refers to two main
aspects, first: the shape of the stone i.e., emerald cut, princess cut etc.
second, the proportions, dimensions and finish of a diamond. How a diamond is
cut is also known as the "make".
Depth
The distance between
the culet (bottom) and the table (top) of the diamond, recorded in a laboratory
report to the one hundredth of a millimeter.
Depth %
The depth
of the diamond divided by its width.
An enhancement process by which a
laser is used to drill into a diamond to reach a dark colored inclusion. Acids
are then introduced through the small hole and into the inclusion, which is then
burned out leaving a less noticeable white or crystalline imperfection. The acid
is then removed by vacuum. A laboratory report is your best protection against
drilled stones.
EGL
European Gemological Laboratory. Widely
respected in the trade offering independent grading certificates.
Eye-clean
Free of any internal inclusions to the naked eye,
when viewed from the top.
Facets
The polished planes
(surfaces) of a diamond, defining its dimensions.
Feather
A
common, naturally occurring white feather shaped inclusion, which may or may not
be visible to the naked eye.
Fire
Along with life,
scintillation, refraction and dispersion, a word used to describe the ability of
a diamond to "sparkle" in response to the introduction of light.
Fluorescence
Also known as photoluminescence, the property
some diamonds have that makes them glow a certain color (usually blue) when
placed in an ultraviolet rich environment. Strong, very strong and sometimes
medium blue fluorescence may slightly improve the color appearance of diamonds
rated "H" in color or below (I,J,K etc). Such fluorescence in some of the
"lower" colors may even enhance the value of these stones. Strong blue
fluorescence in diamonds D to F color may impart a very slightly bluish
appearance and may, in turn, detract a few percent from the value of those
diamonds. Some diamonds with unusually strong blue fluorescence can have a hazy
or "milky" appearance.
Fracture
An internal or external break
or crack, which may look like a common flaw. A fracture may have occurred at any
time during the natural creation of the stone, or even at any time during its
use.
Fracture Filling
An enhancement process by which an
inclusion is injected with filler material to mask its presence. A laboratory
report such as those we offer is your best protection against fracture filled
stones.
GIA
Gemological Institute of America, the single most
widely accepted diamond authority. An independent, third party grading service
offering diamond grading reports.
Girdle
The outermost edge of
a diamond, it can be unpolished or polished and faceted and of varying
thicknesses. The girdle is generally where the diamond is held in a setting.
I1
A term used to describe the clarity of the diamond,
meaning "Imperfect." A diamond rated I1 usually has inclusions visible to the
unaided eye. There are three grades in the I range: I1, I2 and I3.
I2
A term used to describe the clarity of the diamond, slightly more
imperfect than I1. There are three grades in the I range: I1, I2 and I3.
I3
A term used to describe the clarity of the diamond,
slightly more imperfect than I2. There are three grades in the I range: I1, I2
and I3.
IF
Internally flawless. Free of any internal
imperfections to the trained eye at 10-power magnification.
Inclusion
A naturally occurring imperfection often referred to
as a feather, pinpoint, cloud, crystal, spot, etc. in the diamond that may or
may not be visible to the naked eye.
Make
The proportions and
dimensions of a diamond, also known as cut.
Melee
Diamonds
that weigh less than 1/5 of a carat are known as melee. They are usually side
diamonds or accent diamonds in a larger piece of jewelry or set in "clusters."
Natural
An external characteristic on a diamond's surface. A
natural is actually an unpolished portion of the "skin" of the rough diamond.
Pavilion
The faceted portion of the diamond that is below the
girdle.
Pinpoint
A very small inclusion inside a diamond.
Point
A unit of weight measure equal to 1/100 of a carat. A
1/2 carat diamond weighs 50 points, etc.
Polish
The overall
quality and uniformity of the polish of a diamond. Graded from poor to
excellent, it is based on the final finish applied to the facets and facet
junctures by the cutter.
Refraction
Along with life,
scintillation, brilliance, and dispersion, a word used to describe the ability
of a diamond to "sparkle" in response to the introduction of light.
Scintilation
Along with life, brilliance, refraction and
dispersion, a word used to describe the ability of a diamond to "sparkle" in
response to the introduction of light.
SI1
A term used to
describe the clarity of the diamond with slight inclusions. The GIA recognizes
two grades in the SI range: SI1 and SI2. The EGL recognizes a third SI grade,
SI3. Well cut diamonds in the SI range should be completely to nearly clean to
the unaided eye.
SI2
A term used to describe the clarity of
the diamond with slight inclusions. The GIA recognizes two grades in the SI
range: SI1 and SI2. The EGL recognizes a third SI grade, SI3.
SI3
A term used to describe the clarity of the diamond with slight
inclusions. The GIA recognizes two grades in the SI range: SI1 and SI2. The EGL
recognizes a third SI grade, SI3.
Solitaire
A single diamond
set in a mounting that shows off the simplicity and elegance of the stone.
Sparkle
Along with life, fire, scintillation, refraction,
dispersion, a word used to describe the brilliance of a diamond.
Symmetry
The overall uniformity of the cut of a diamond.
Graded from poor to excellent, it is based on the diamond's proportions and the
relation of one facet to another.
Table
The top and largest
facet of a diamond, it is where much of its light both enters and exits the
diamond.
Table %
A measurement, which relates the diameter of
the table divided by its depth.
VS1
A term used to describe
the clarity of the diamond, meaning very slight inclusions. There are two grades
in the VS range: VS1 and VS2. The imperfections in VS stones can be quite
difficult to find even with the aid of 10-power magnification.
VS2
A term used to describe the clarity of the diamond, meaning very slight
inclusions. There are two grades in the VS range: VS1 and VS2. The imperfections
in VS stones can be quite difficult to find even with the aid of 10-power
magnification.
VVS1
A term used to describe the clarity of
the diamond, meaning very, very slight inclusions. There are two grades in the
VVS range: VVS1 and VVS2. Imperfections in VVS stones should be extremely
difficult to find even to the trained eye with the aid of 10-power
magnification.
VVS2
A term used to describe the clarity of the
diamond, meaning very, very slight inclusions. There are two grades in the VVS
range: VVS1 and VVS2. Imperfections in VVS stones should be extremely difficult
to find even to the trained eye with the aid of 10-power magnification.
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