I can not remember who was asking about the coloured diamonds but;
sciencenet.org.uk
"Why do diamonds vary in colour?
Some of colour variations occur because of trace substances in the diamond itself. For
example yellow diamonds are yellow because of trace amounts of nitrogen and blue
diamonds are blue because of boron. However there are other reasons to explain the
colour variations. Green diamonds are green but only on the surface because they have
been naturally irradiated - approximately 85% of all radiation on earth is actually naturally
occuring, as a result of elements breaking down. Finally, brown, pink and red diamonds
are coloured due to a plastic deformation of the crystal lattice structure of the diamond
itself."
jewelryexpert.com
"Fancy Colored Diamonds: Picassos for Peanuts
One of the four "C's" affecting diamond value is color. It sometimes surprises people
to learn that diamonds occur throughout the entire spectrum of colors. Most
diamonds range from an inexpensive grade, with a slightly imperceptible tinge of
yellow brown, up to the rare stones that are absolutely colorless (white) and quite
expensive. Some even rarer stones display intense natural shades of yellow, brown,
green, red, pink or amber and are termed Fancies.
Fancy diamonds are indeed quite rare; a diamonds chances of displaying an intense
fancy color are roughly 1 in 2500!! Some fancy colors are rarer than others. The
more encountered colors of yellow, brown and grey are quite affordable, while the
rarer pinks, greens, blues and reds fetch much higher prices.
Fancy yellow and brown diamonds certainly offer a
potential bargain to the would-be
shopper/investor. Although these colors are at
least 10 times as rare as their white diamond
counterpart, they are not 10 times more
expensive. On the contrary, slightly off-colored
yellows and browns may be less expensive than
white stones, while the intense fancy yellows and
browns may be only 25-35% more expensive than white stones.
Since the term fancy covers a broad spectrum of hues and intensities, a yellow
diamond could vary from a straw-like color, through to taxicab yellow. Unfortunately,
some stores use the term "canary" to describe any yellow diamond. However, this
term should only be reserved for those rare stones which display an intense yellow
hue with a warm orange tinge.
Fancy brown diamonds offer an ideal choice for men's jewelry because brown is
considered a masculine color. The brown diamond displays the brilliance (white light),
fire (spectral colors), scintillation (sparkle) and durability of its white counterpart, yet
in a color that best accents a man's wardrobe and style.
What causes the color in diamonds? Diamonds are made up of primarily carbon
molecules, however, certain atomic impurities get trapped within the crystal lattice and
impart color. Nitrogen, for example, is the element that causes yellow and brown,
whereas boron creates the color blue. The more of the impurity trapped throughout
the crystal structure, the more the intense color. Absolutely colorless diamonds lack
these impurities.
Although the off-colored diamonds are more common and, therefore, less costly, they
can be set in a yellow gold to accent their warm color and still display a magnificent
brilliance.
The hue (spectral color), tone ( lightness versus darkness) and intensity (purity) of a
diamond's color are the most important factors affecting price. Clarity is not as
important, especially since the darker colored diamonds mask inclusions which might
be more visible in a colorless stone.
A word of caution when shopping for fancy diamonds. There are many fancy diamonds
on the market with an artificially induced color. Irradiated diamonds are generally
more intense in a color than natural fancy diamonds, and are certainly less expensive.
If you do purchase a fancy diamond, ask for the origin of color ( i.e.: natural versus
treated) to be specific on the bill of sale and/or the appraisal. You should only pay the
price for a "natural color" if it is truly natural.
As always, ask your jeweler to explain all the four "C's" of the diamonds shown to you,
and describe their quality on either of the two internationally accepted scales (GIA and
AGS)."
siriusdiamonds.com
"FANCY COLORED DIAMONDS
If a diamond is of a rich unusual color,
that is pleasing to the eye, it is
considered unique and has a
relatively high value. Colored
diamonds in the trace go under the
name of Fancy Colors. The color
palette of fancy colored diamonds
ranges from pink through red, blue,
green, cognac, coffee and yellow.
Two very well known examples are
the HOPE diamond which is a deep
blue and the TIFFANY diamond which
is a brilliant yellow.
The most valuable diamonds,
however, are the completely
colorless stones. In this respect
diamonds are the only gemstone
whose colorlessness render them
more valuable."
sddiamond.com
"The most Internationally accepted color scale in the diamond industry is provided by the Gemological Institute of America
(G.I.A.). G.I.A. introduced their color grading scale in the late 1950's. Color with reference to diamond grading refers to subtle
differences in the body color or hue. The G.I.A. color scale runs a range from D thru Z, or colorless to light yellow. The
distinctions between color grades are very subtle, and for the most part are undetectable to the untrained eye. In general, all
diamonds in the D to Z range are considered 'white' in color.
Price vs Color
Naturally occurring rare fancy colors such as blue, pink, green, and red can bring the highest prices
for diamonds"
colored-diamonds.com
colored-diamonds.com page3...6.html
The majority of people will say that they are unaware that diamonds come in any color other than white. Yet, if you ask those
same people to name the most famous diamonds in the world, chances are, the top two diamonds that will be mentioned will be
the 45.52 carat "Hope" diamond in the Smithsonian and the 128.51 carat "Tiffany" diamond. The "Hope" is dark grayish blue
and the "Tiffany" is bright yellow. Although there are a large number of white diamonds that have been named, the public is
unaware of them. Fame in diamonds comes from beauty, rarity and value. The beauty of fancy colored diamonds is
breathtaking. Their rarity is incomparable. The price per carat for some fancy colored diamonds makes the value of the finest
white diamonds look like gravel by comparison. By 1991, fancy colored diamonds held 19 of the top 20 per carat price
records at auction, blowing away white diamonds, emeralds, rubies and sapphires!
Considering how intriguing these diamonds are, the market that purchases them must also be intriguing. It is. From upper middle
class people who want the incredible and unusual beauty of a 3 carat fancy yellow starburst cut diamond at approximately
$33,000 to those international jet setters who will buy a 5 carat intense blue pear shaped diamond to wear to some occasion
for $2,500,000, the buyers form a who's who of astute international consumers, investors and business people. The highest
prices paid for these types of gems are at famous retail jewelry stores and high profile auctions. Often the richest consumers use
dealers to buy for them lest their fame drive up the price of a particularly desirable stone.
More unexpectedly, there is a very fast growing section of this buying group who buy fancy colored diamonds and never intend
to wear the stones themselves or have their names known by anybody. The unique concentration of wealth per carat, the
fascinating beauty, and the fact that they have never gone down in value since prices have been regularly recorded make fancy
blue, pink, red, green, purple and yellow diamonds the most singly unique and private forms of wealth known to man. If you
could find 142, 1 carat fancy blue diamonds (1 troy ounce), all eye clean, the horde would be worth in the neighborhood of
$21,300,000. Unfortunately, it would take several life times to collect that many one carat stones, if it could be done at all. By
contrast that amount of money in pure gold would weigh a mere 4,437.5 troy pounds - over two tons!
vandaaz.com
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