
Diamond is the ultimate gemstone, having few weaknesses
and many strengths. It is well known that Diamond is the
hardest substance found in nature, but few people
realize that Diamond is four times harder than
the next hardest natural mineral, corundum (sapphire and
ruby). But even as hard as it is, it is not impervious.
Diamond has four directions of cleavage, meaning that if
it receives a sharp blow in one of these directions it
will cleave, or split. A skilled diamond setter and/or
jeweler will prevent any of these directions from being
in a position to be struck while mounted in a jewelry
piece.
As a gemstone, Diamond's single
flaw (perfect cleavage) is far outdistanced by the sum
of its positive qualities. It has a broad color range,
high refraction, high dispersion or fire, very low
reactivity to chemicals, rarity, and of course, extreme
hardness and durability. Diamond is the April
Birthstone.
Diamonds may be nearly any color in the rainbow plus
browns, grays, and white. Shades of yellow are most
common, followed by colorless. Blue, black, reddish, and
greenish are more valuable (some extremely so).
|
|
|
In terms of it's physical properties, diamond is the ultimate
mineral in several ways:
-
Hardness: Diamond is a perfect "10", simply the hardest
substance known by a wide margin.
-
Clarity: Pure diamond is completely colorless and
transparent over a larger range of wavelengths (from the
ultraviolet into the far infrared) than is any other solid or
liquid substance - nothing else even comes close.
-
Thermal Conductivity: Diamond conducts heat better than
anything - five times better than the second best element,
Silver! This characteristic is the basis for "diamond tests", as
it is simple and cannot be faked.
-
Dispersion: Diamond has a relatively high optical dispersion
which gives diamond the "fire" that makes it so desirable.
Diamonds may be nearly any color in the rainbow plus browns,
grays, and white. Shades of yellow are most common, followed by
colorless. Blue, black, reddish, and greenish are more valuable
(some extremely so).
|
|
Diamonds are
found in a type of rock called "Kimberlite", which comprises the
core of certain volcanoes over especially thick portions of the
earth's crust. This hard stone is mined and then crushed between
giant steel rollers. The kimberlite is reduced to fine gravel, yet
the extremely hard diamonds come out unharmed! Water is added and a
grease covered roller sorts the diamonds from the gravel, as the
diamonds stick to the grease. Typically, a single carat of diamond
is recovered from a ton of ore.
Diamonds are
found in many areas including South Africa, Russia, and even in
Arkansas in the USA. In all cases, diamonds formed deep within the
earth's mantle, and were brought to the surface in volcanic
eruptions. In many cases, the diamonds weathered out of the
kimberlite by natural processes, and were transported downstream by
water. Many diamonds are mined in the resulting alluvial deposits
in areas such as along the coast of South Africa.
|