Loose Diamonds - Most Popular Diamond Cuts

Round

For almost 100 years, cutters have been perfecting their art in effort to achieve the grandeur and luster of the round diamond.

Asscher

A uniquely modified square Emerald. Being a trademark design cut, Asscher diamonds are short in supply and highly sought-after.

Princess

Brilliant, square diamonds with no trimmed corners. An extremely popular choice for engagement rings.

Radiant

Rare and unique, the Radiant Diamond features beautiful barely trimmed corners. This blazing cut makes an exceptional choice.

Cushion

Gently rounded like a cushion, this exceptional cut has been in high demand for over a century as a solitaire.

Pear

Pear shaped diamonds go back to the 1400s. These stones are most popular as engagement rings & pendants.

Marquise

This slim and point-ended cut, set parallel to the finger & often embellished by accent stones. Popular for wedding rings.

Heart

The heart shape is mostly in demand in recent years for pendants. High color level is important as it is visible at the corners.

Oval

Elegant and luminous, oval diamonds compliment feminine fingers, and are usually extremely fashionable among small-handed women.

Emerald

A rectangular cut of the emerald diamonds featuring trimmed corners and rectangular facets, popular when set with accent stones.

Triangle

Also "Trilliant Diamonds", these stones are often used in stud earrings. Chosen wisely, this cut can be a splendid center stone.

source : diamonds-usa.com

Black Diamonds

What are Black Diamonds, as seen in most jewelry?

Black diamonds are typically enhanced. Black diamonds are genuine diamonds treated with radiation to make their color appear black. Under normal lighting conditions the color enhanced black diamond looks black. However, it is actually very dark green. To observe the very dark green color, a fiber-optic light source can be placed near a thin edge of the diamond (such as the girdle or culet). This allows the light to illuminate some of the interior of the stone. The very dark green color that becomes visible is commonly seen in enhanced black diamonds. The very dark green color that is seen is never seen in natural diamonds. It is a result of radiation treatment.

Famous Black Diamonds

The Black Orloff

The Black Orloff (Orlov) cushion cut diamond (shown left) which still weighs in at a very respectable 67.50 carats. It is reported to have belonged to a nineteenth-century shrine near Pondicherry, India, and to have weighed 195 carats in the rough. Set in a diamond and platinum necklace, the Black Orloff has been widely exhibited. In 1969, the stone was sold for $300,000. It was resold in 1990 at Sothebys for $99,000. Also called the Eye of Brahma Diamond. The diamond is currently owned by Dennis Petimezas, a diamond dealer from Pennsylvania who bought the diamond for an unspecified sum in 2005.

"The Gruosi" Black Diamond

Upon creating amazing black diamond jewelry for his luxury jewelry house de Grisogono, chairman and founder Fawaz Gruosi enjoys a special place in diamond history: he is credited with popularizing the fascination with black diamonds in 1996 - a fascination that continues today.

He also had a rare opportunity - a rare opportunity even for a grand jeweler like himself: he got to name a diamond. Naming a diamond is something reserved only for original buyers of a rough diamond. The de Grisogono founder chose the name "The Gruosi" for the incredible 115.34-carat black diamond. In fact, Fawaz Gruosi has actually been involved in naming two diamonds - the other being the 312.24-carat "The Spirit of Grisogono," also a black diamond with the famous Swiss jeweler Mr. de Grisogono. These two black diamonds are the two largest black diamonds in the world.

sources : generousgems.com,blackdiamonds.co.uk,vialuxe.com

Diamond : as a mineral

Diamond
A scattering of round-brilliant cut diamonds shows off the many reflecting facets.
General
Category	Native Minerals
Chemical formula	C
Identification
Molecular Weight	12.01 u
Color	Typically yellow, brown or gray to colorless. Less often in blue, green, black, translucent white, pink, violet, orange, purple and red.
Crystal habit	Octahedral
Crystal system	Isometric-Hexoctahedral (Cubic)
Cleavage	111 (perfect in four directions)
Fracture	Conchoidal - step like
Mohs Scale hardness	10[1]
Luster	Adamantine
Polish luster	Adamantine
Refractive index	2.4175–2.4178
Optical Properties	Singly Refractive
Birefringence	none
Dispersion	.044
Pleochroism	none
Ultraviolet fluorescence	colorless to yellowish stones - inert to strong in long wave, and typically blue. Weaker in short wave.
Absorption spectra	In pale yellow stones a 415.5 nm line is typical. Irradiated and annealed diamonds often show a line around 594 nm when cooled to low temperatures.
Streak	White
Specific gravity	3.52 (+/- .01)
Density	3.5-3.53
Diaphaneity	Transparent to subtransparent to translucent

Diamond is an allotrope of carbon. It is the hardest known natural material and the third-hardest known material after aggregated diamond nanorods and ultrahard fullerite. Its hardness and high dispersion of light make it useful for industrial applications and jewelry.

Diamonds are specifically renowned as a material with superlative physical qualities; they make excellent abrasives because they can be scratched only by other diamonds, Borazon, ultrahard fullerite, or aggregated diamond nanorods, which also means they hold a polish extremely well and retain their lustre. Approximately 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion, and about 100,000 kg are synthesized annually.^[2]

The name diamond derives from the ancient Greek adamas (αδάμας; “invincible”). They have been treasured as gemstones since their use as religious icons in ancient India and usage in engraving tools also dates to early human history.^[3][4] Popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns. They are commonly judged by the “four Cs”: carat, clarity, color, and cut.

Roughly 49% of diamonds originate from central and southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia. They are mined from kimberlite and lamproite volcanic pipes, which brought to the surface the diamond crystals from deep in the Earth where the high pressure and temperature enables the formation of the crystals. The mining and distribution of natural diamonds are subjects of frequent controversy such as with concerns over the sale of conflict diamonds (aka blood diamonds) by African paramilitary groups.

references :
1.^ ^{a b c d e f g h i j k} Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
2.Yarnell, Amanda (2004). "The Many Facets of Man-Made Diamonds". Chemical and Engineering News 82 (5): 26–31. American Chemical Society. ISSN 0009-2347. Retrieved on 2006-10-03
3.Pliny the Elder. Natural History: A Selection. Penguin Classics, p. 371. ISBN 0140444130
4."Chinese made first use of diamond", BBC News, 17 May 2005. Retrieved on 2007-03-21
5.Wikipedia,the free encyclodepia