flaw (scratch or abrasion) on the surface of a stone.
light reflected up from the surface of a stone. Brilliance is maximized
by cutting a stone to the correct proportions.
58-facet round stone.
unit of weight for a stone, equivalent to 200 milligrams, or one fifth
of a gram.
grade given to a stone to describe how many inclusions the stone has.
The clarity scale ranges from FL (flawless), meaning a stone has no
internal or external flaws, to I3 (severely included), meaning a stone
has many flaws clearly visible to the naked eye.
cluster of small inclusions inside a stone.
grade given to a stone to describe the color tones of the stone. The
color scale ranges from D, meaning completely colorless, to Z, fancy yellow.
As the scale moves from D to Z, it indicates increasing levels of yellow
and brown tone.
facet on the very bottom of a stone. If the culet is medium to large,
when the stone is viewed from the table, it will look like there is
a hole in the bottom of the stone.
used to refer to both the shape of a stone (round, pear, oval, etc.) and
the make (the exact geometric proportions to which a stone is cut).
The make of a stone is the most important factor in determining how much
sparkle comes from a stone.
stones that are perfectly proportioned (having depth percentages and
table percentages that maximize fire and brilliance) and have high grades
on polish and symmetry. These stones have had the finest craftsmanship
to maximize the beauty of the stone.
cut to fit very strict requirements for depth percentage and table percentage.
These outstanding proportions maximize fire and brilliance in the stone.
cut with acceptable, but not perfect, cut proportions. They generally
have very good brilliance and fire and make excellent jewelry.
cut to less perfect proportions. They have been cut to maximize the weight
of the stone, and sacrifice fire and brilliance. While less expensive
than stones shown as having Good and Very Good cuts, they do not have
the sparkle people expect from a stone.
||Poorly cut stones that look dead
to the eye. These stones are not recommended for fine jewelry.
||The height of a stone (measured
from the culet to the table).
||The height of a stone (measured
from the culet to the table) divided by the width of the stone. The
depth % is critical to creating brilliance and fire in a stone; a depth
% that is too low or too high will cause a stone to lack sparkle.
||A stone that has no inclusions visible
to the naked eye.
||The flat polished surfaces on a stone.
A round brilliant stone has 58 facets.
||Colored light reflected from within
a stone. Fire is maximized by cutting a stone to the correct proportions.
||A glow, usually of a bluish color,
which emanates from certain stones when exposed to ultraviolet light.
Strong fluorescence should be avoided, but faint fluorescence usually
does not affect the appearance of a stone.
||The narrow band around the width of
a stone. The setting usually holds the stone around the girdle.
||A flaw within a stone, such as a
spot or irregularity in the crystal structure of the stone. Inclusions
can either be visible with the naked eye (usually SI2 clarity and below)
or visible only under magnification.
||The proportions to which a stone
has been cut. A good make will have proportions that maximize the brilliance
and fire of a stone. A poor make will lead to a stone that has little
sparkle due to the inability of the cut to properly reflect light.
||The bottom portion of a stone, from
just below the girdle to the bottom.
||A weight measure equal to one one-hundredth
of a carat. (A 0.50 carat stone is said to be 50 points.)
||A grade given to the external finish
of a stone. The polish scale ranges from poor to excellent.
||The combination of fire and brilliance;
the amount of light that reflects out of a stone.
||A grade given to the overall uniformity
of a stones cut. The scale for symmetry ranges from poor to excellent.
Poor symmetry will hurt the sparkle of a stone. Diamonds with symmetry
grades of good to excellent are recommended.
||The largest facet on a stone, located
on the top of the stone facing out from the setting.
||The width of the table divided by
the total diameter of the stone. The table % is critical to creating
sparkle in a stone; a table % that is too low or too high will cause
a stone to lack sparkle.