The Grading of a diamond consists of the 4 "C's":
Carat,
Cut, Color,
Clarity.
The hardness, brilliance, and
sparkle of diamonds make the unsurpassed as gems. In the
symbolism of gemstones, the diamond represents steadfast love
and is the birthstone for April. Grading is based on
purity, which varies from perfectly clear, and extremely purse
stones to those with many impurities and flaws. Large
demand provided an incentive for the production of false
diamonds as early as 1675 in Paris.
Colorless or pale blue diamonds are
the most valuable. The most common diamonds found in the
marketplace today are gray or brown and are translucent or
opaque, but better-quality diamonds are mixed in.
Diamond stones are weighed in
carats and can be found in three types of deposits.:
alluvial gravels, glacial tills and kimberlite pipes. Only
in kimberlite pipes are they present in the original rock in
which they were formed probably lying at depth of more than 75
miles. Diamonds found alluvial and glacial gravels must
have been released by fluvial or glacial erosion of the
kimberlite matrix and then redeposited in rivers or in glacial
tills.
A very high refractive power gives
the diamond its extraordinary brilliance. A properly cut
diamond will return a greater amount of light to the eye of the
observer than will a gem of lesser refractive power and will
thus appear more brilliant. The high dispersion gives
diamonds their fire, which is caused by the separation of white
light into the colors of the spectrum as it passes through the
stone.
Diamond Engagement Ring
The scratch hardness of diamond is
assigned the value of 10 on the Mohs scale hardness; corundum,
the mineral next to diamond in hardness, is rated as 9.
Actually, diamond is very much harder than corundum; if the Mohs
scale were linear, the diamond's value would be about 42. The
hardnes of a diamond varies significantly indifferent
directions, causing cutting and polishing of some faces to be
easier than others. In the atomic structure of diamond, as
determined by X-ray diffraction techniques, each carbon atom is
linked throughout the crystal. This close-knit dense,
strongly bonded crystal structure yields diamond properties that
differ greatly from those of graphite, native carbon's other
form.
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