The birthstone
for April is the diamond.Diamond is the best known gemstone, famous for its remarkable
brilliance. Ancient civilizations were fascinated by the exceptional
hardness of diamond, although colored gems were regarded as more
aesthetically pleasing. The Greek philosopher, Plato, called diamond
the "noblest" of all gems. Diamond was extremely rare
up to the eighteenth century and was only fully appreciated after
the modern type of brilliant cut, which shows it in all of its
glory, was developed at the beginning of the twentieth century.
In most cases, diamond is almost colorless, but can also appear
as yellow, brown, yellow-brown. Very rarely, diamonds may also
be pink to reddish, blue, blue-gray, pale green, or violet. Throughout
history, diamonds were consistently linked with mystical powers,
courage, and virtue.
Mohs hardness: 10
Refractive Index: 2.41
Specific Gravity: 3.52
The toughness of diamonds is good. Diamond may be cleaned by any
of these methods: steaming, ultrasonic, boiling, jewelry cleaner,
soap, or an untreated cloth.
When buying a diamond, consider the following 4-C's:
Cut
The cut of a diamond has the greatest influence on the diamond's
fire and brilliance. A round, brilliant cut diamond has fifty-eight
(58) facets. When well proportioned, this shape best shows the
brilliance of the stone because it allows the most light to be
reflected back to the eye of the observer. Stones that appear
lifeless or seem dark in the center are probably poorly cut.
Carat
The term carat comes from the ancient practice of weighing
diamonds against the seeds of the carob tree. The system was eventually
standardized, and one carat was fixed at 0.2 grams. One carat
is divided into 100 points, so a quarter carat diamond is 25 points,
or 0.25 carats. Although carat is a unit of weight, not size,
the carat weight of a diamond has come to refer to particular
sizes. If properly cut, diamonds of the same weight should be
about the same size. These sizes don't apply to other gems, however,
because they have different specific gravities than diamonds.
Color
Diamonds can cover the entire spectrum of colors. The majority,
however, range from those with a barely perceptible yellow or
brownish tint, up to those that are very rare and described as
colorless. Colorless diamonds are the most desirable since they
allow the most reflection of light. Off white diamonds absorb
light, inhibiting brilliance. You can best observe diamond color
by placing the stone table side down on a flat, white surface
or grading trough, and examining it from different angles. Next,
place it pavilion side down with the culet facing you, and examine
it through the pavilion facets.
Clarity
Most diamonds contain minute traces of non-crystallized carbon
and internal stress fractures. Called inclusions, most of these
are not apparent to the naked eye, but can be seen in loose stones
under magnification. Perfect clarity means that no inclusions
are discernible when the diamond is examined under a 10X lens.
Inclusions greatly affect the beauty and value of a diamond because
they absorb the light rather than allowing it to be reflected
back through the front of the stone. How much they reduce the
value of a diamond depends on their size and number, and their
position within the stone. An inclusion in the center of a diamond
beneath the table is more visible than one near the edge. It also
may be mirrored many times by adjoining facets. The GIA clarity
grading scale gives a description of each grade.
