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.[1] 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[1] Polish luster Adamantine[1] Refractive index 2.4175–2.4178 Optical Properties Singly Refractive[1] Birefringence none[1] Dispersion .044[1] Pleochroism none[1] Ultraviolet fluorescence colorless to yellowish stones - inert to strong in long wave, and typically blue. 
Weaker in short wave.[1] 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.[1] Streak Colorless Specific gravity 3.52 (+/- .01)[1] Density 3.5-3.53 Diaphaneity Transparent to subtransparent to translucent Diamond is the hardest natural material known to man 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. About 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion.[citation needed] 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,
system Isometric-Hexoctahedral (Cubic) Cleavage 111 (perfect in four directions) Fracture Conchoidal -
step like Mohs Scale hardness 10[1] Luster Adamantine[1] Polish luster Adamantine[1] Refractive index 2.4175–2.4178 Optical Properties Singly Refractive[1] Birefringence none[1] Dispersion .044[1] Pleochroism none[1] Ultraviolet fluorescence colorless to yellowish stones - inert to strong in long wave, and typically blue. 
Weaker in short wave.[1] 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.[1] Streak Colorless Specific gravity 3.52 (+/- .01)[1] Density 3.5-3.53 Diaphaneity Transparent to subtransparent to translucent Diamond is the hardest natural material known to man 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. About 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion.[citation needed] 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,
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