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 Brilliant
Sparkle, Beautiful and Durable Gem
Diamond is the hardest and most
brilliant of all precious gems. The word diamond fills the mind with images of a
sparkling and dazzling transparent gemstone, the incomparable beauty and purity
that has mesmerized the human mind since ancient times.
Spectrum of Colors in
Diamond through its Sparkles
Thinking of a diamond brings a
colorless transparent gem as an image in our mind, but diamond is actually found
in all colors of spectrum, ranging from pink, blue, black, yellow, grey, orange
and even white. Colors of spectrum belong to certain energy levels. If these
energy levels are sufficient to move any electron in the material to a higher
level, that part of the spectrum gets absorbed, and the rest of the light is
emitted out. The presence of nitrogen atoms in a diamond crystal absorbs violet
and blue parts of the spectrum, so the crystal appears yellow. In a pure carbon
crystal, the spectrum of light has insufficient energy to move the strongly
bonded electrons to any level, so no part of light is absorbed, and therefore,
pure diamonds are colorless.
Properties of Diamond
Whenever we think of and hear about diamonds, we almost always think of diamond
as a gem in jewelry because of its popularity as a gem, its stories, fascination
throughout the history including the ancient history, and all other amazing
facts, lore and beliefs. However the utility of diamond is not limited to it
being just a gem. It is widely used as an industrial material and also for
scientific use. Read about its physical properties below and you will get to
know why we all have talked about, sought and fought for diamonds though the the
long history of diamonds.
Hardness
Diamond is the hardest known crystalline material composing mainly of carbon
atoms bonded together by covalent bonds, each carbon atom bonded with four other
carbon atoms. This forms a symmetrical and regular tetrahedral structure, which
imparts diamond its hardness and light dispersion properties. This combination
of hardness and brilliance makes it popular in jewelry as well as in industrial
applications. It is the purest form of carbon.
Diamond’s hardness
helps them against abrasiveness, as a diamond can be scratched only by another
diamond or something even harder, therefore, they retain luster over long
periods of time and hold a polish extremely well, that’s why it is preferred
gemstone for engagement and wedding rings which are often worn daily.
The hardest
diamonds in the world are found in New England area in New South Wales,
Australia. The size of the diamonds found here is generally small and are used
mostly used to polish other diamonds. These diamonds are hardest due to the
crystal formation, which is formed in a single stage as compared to other
diamonds, which are formed by multiple growth stages which leads to more number
of inclusions and defect planes which affect their hardness.
The diamond’s
hardness also adds to its utility for cutting and grinding tools and abrasives.
It can be used for polishing, cutting and wearing of other materials including
diamond. Industrial diamonds are not suitable to be used as gems and therefore
sometimes synthetically produced.
Though diamond is
the hardest known material, it is not surely the toughest one. Macroscopically
it is resistant to breakage but it can still be shattered along a few
crystallographic planes, where the number of bonds as less as compared to other
directions in the structure, quite neatly providing perfect cleavage which comes
of use for diamond cutters.
Conductive
Pure diamonds do not exhibit electrical conductivity, because there are no free
or lose electrons in its structure; the carbon atoms share four electrons of
their outermost shell with four other atoms to complete the octet. So there is
no question of any lose electrons anywhere in its structure. But if there are
inclusions of some atoms (impurities), some electrical conductivity (loosely
bound electrons) is possible as the included atoms may have more or less
electrons than “four" in their outermost shell. Diamonds are electrical
insulators, but the impurities and inclusions make them work like
semiconductors.
Density
Diamond is denser as compared to graphite which is also pure carbon; the only
difference lies in the type of bonding. Density is the ratio of mass to volume
of a substance. The density of diamond is 3.51 grams per cubic centimeter as
compared to 2.2 for graphite. This high density owes to strong bonds of carbon
atoms formed under high pressure and temperature conditions under the earth’s
surface.
Diamond’s great
ability to refract light makes it lustrous and brilliant in appearance. The
light entering a diamond gets bent at certain angles, depending on the cut, and
slowed down due to material properties and comes out after getting reflected
from different angles. Speed of light in vacuum is 1.86X106 miles per second.
Density of diamond plays an important role here. Denser materials slow down
light passing through them in greater magnitude as compared to those with less
density which also determines their refractive index (ratio of speed of light in
material to that in vacuum) . In a diamond, the speed of light gets reduced to
7.7X104 miles per second which is almost the maximum for any transparent
material. The refractive index of diamond is 2.42 which is much higher than
glass (1.52). The amount of light reflected by a material is also determined by
the refractive index and diamond exhibits maximum reflectance among all
transparent materials.
Gemstone
Another most prized attribute of a diamond as a gemstone, is its ability to
disperse light into the seven colors of spectrum. The “fire" and the glitter of
the gem is because of this amazing ability that has made diamond unique and
precious among other gemstones. Greater the dispersion, greater is the distance
between the dispersed colors, which can make the colors vivid and easy to
distinguish. The refractive index of a material varies with the wavelength. It
means short wavelengths (Violet and Blue colors) are bent more as compared to
longer (Yellow and Red colors) ones. The coefficient of dispersion judges this
variation in the angles for different wavelengths, the greater the coefficient,
the greater is the angular spread of different colors of white light falling at
a certain angle on the material. The dispersion of light decides the gem’s
brilliance.
Structure of a Faceted Diamond
The natural beauty of a diamond
is enhanced by how it is cut because the fluorescence, light dispersion etc.
depends on how well it is cut. The widest part of any round diamond, the
part in the middle, is known as the girdle, which is probably quite self
explanatory. The top part, above the girdle is known as the crown, and the
lower part below the girdle is known as the pavilion. The point or small
facet at the very bottom is known as the culet........
Read more...
Get to Know Diamonds
A symbol of innocence, justice, faith and strength, the diamond was
believed to make its wearers courageous and victorious over their
enemies. When set in gold and worn on the left side, it held the power
to drive away nightmares and soothe savage beasts. Diamonds were even
thought to be so powerful that they could stop lechery.
Diamonds have lured and
fascinated us for centuries. Their ores and lore recorded romantic and
bloody events in the past. Diamonds have been long cherished and sought
after, fought over and killed for in the human history simply because of
its beauty and the fascination....
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