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Thaks for you detailed answer...tom science

2006-08-21 03:10:53 · 21 answers · asked by tom science 4 in Science & Mathematics Earth Sciences & Geology

21 answers

Thousands of years and compression.

2006-08-21 03:15:00 · answer #1 · answered by JeffE 6 · 1 0

Diamonds typically crystallize in the face-centered cubic crystal system and consist of tetrahedrally bonded carbon atoms. The unit cell of diamond has a two atom basis at (0,0,0) and (1/4,1/4,1/4), which means half of the atoms are at lattice points and the other half are offset by (1/4,1/4,1/4), where 1 is the length of a side of the unit cell. Diamond's density is 3.52 g·cm−3.

The tetrahedral arrangement of atoms is the source of many of diamond’s properties. The carbon atoms in Graphite, the other major allotrope of carbon, display a different (nontetrahedral) connectivity and as a result shows dramatically different physical characteristics: graphite is a soft, dark gray, opaque mineral. Other elements of the carbon group such as silicon crystalize like diamond.

Lonsdaleite is a polymorph of diamond (and a distinct mineral species) that crystallizes with hexagonal symmetry. It is rarely found in nature but is characteristic of synthetic diamonds. A cryptocrystalline variety of diamond is called carbonado. A colorless, grey or black diamond with a tiny radial structure is a spherulite.

2006-08-21 03:17:12 · answer #2 · answered by Michael 5 · 0 0

Carbon is one of the more common elements. Carbon is stable in crystalline form known as diamonds at extreme pressures and temperatures found in the mantle. Diamonds are typically found at the surface in Kimberlite pipes that apparently represent ancient volcanoes shooting up mantle material at speed sometimes greater than the speed of sound. The diamonds are carried up with this material.

2006-08-21 05:14:14 · answer #3 · answered by JimZ 7 · 0 0

Through extremely high pressures and temperatures underneath the earth's crust. Such extreme conditions alter the chemical make-up of certain materials found under the earth's crust containing carbon [e.g. graphite] to become diamonds. This is a very slow process though. It may actually take hundrends of thousands of years to form diamonds.

Hope this helps. =)

2006-08-21 03:23:09 · answer #4 · answered by Aris 2 · 0 0

Formation

Diamonds are formed by prolonged exposure of carbon bearing materials to high pressure and temperature. On Earth, the formation of diamonds is possible because there are regions deep within the Earth that are at a high enough pressure and temperature that the formation of diamonds is thermodynamically favorable. Under continental crust, diamonds form starting at depths of about 150 kilometers (90 miles), where pressure is roughly 5 gigapascals and the temperature is around 1200 degrees Celsius (2200 degrees Fahrenheit). Diamond formation under oceanic crust takes place at greater depths because of higher temperatures, which require higher pressure for diamond formation. Long periods of exposure to these high pressures and temperatures allow diamond crystals to grow larger.
The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.
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The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.

Through studies of carbon isotope ratios (similar to the methodology used in carbon dating, except with the stable isotopes C-12 and C-13), it has been shown that the carbon found in diamonds comes from both inorganic and organic sources. Some diamonds, known as harzburgitic, are formed from inorganic carbon originally found deep in the Earth's mantle. In contrast, eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth's crust through subduction (see plate tectonics) before transforming into diamond. These two different source carbons have measurably different 13C:12C ratios. Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 billion to 3.3 billion years old.

Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles or maccles. As diamond's crystal structure has a cubic arrangement of the atoms, they have many facets that belong to a cube, octahedron, rhombicosidodecahedron, tetrakis hexahedron or disdyakis dodecahedron. The crystals can have rounded off and unexpressive edges and can be elongated. Sometimes they are found grown together or form double "twinned" crystals grown together at the surfaces of the octahedron. This is all due to the conditions in which they form. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf, an opaque gum-like skin.[2]

Diamonds can also form in other natural high-pressure, high-temperature events. Very small diamonds, known as microdiamonds or nanodiamonds, have been found in impact craters where meteors strike the Earth and create shock zones of high pressure and temperature where diamond formation can occur. Microdiamonds are now used as one indicator of ancient meteorite impact sites.

2006-08-21 03:15:53 · answer #5 · answered by Spex 3 · 1 0

Diamond is the hardest known natural material and one of the two best known forms (or allotropes) of carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewelry. (The other equally well known allotrope is graphite.) Diamonds are specifically renowned as a mineral 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 luster. About 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion. About 100,000 kg are synthesized annually.

The name “diamond” derives from the ancient Greek adamas (αδάμας; “invincible”). They have been treasured as gemstones since their use as religious icons in India at least 2,500 years ago—and usage in drill bits and engraving tools also dates to early human history. 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. Although synthetic diamonds are produced each year at nearly four times the rate of natural diamonds, the vast majority of synthetic diamonds produced are small imperfect diamonds suitable only for industrial-grade use.

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 generally mined from volcanic pipes, which are 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 by African paramilitary groups. There are also allegations that the De Beers Group misuses its dominance in the industry to control supply and manipulate price via monopolistic practices, although in recent years the company's market share has dropped to below 60%.

2006-08-21 03:18:00 · answer #6 · answered by Anonymous · 0 0

Diamonds and coal are the same thing, more or less, extremely compressed carbon over millions of years, anyways i'm only in it for the 2pts. Ta.

2006-08-21 03:17:25 · answer #7 · answered by jonlon73 2 · 0 0

When carbon is placed under very high pressure at very hot temperatures it creates Diamonds

2006-08-21 03:16:14 · answer #8 · answered by mavrickatasu 2 · 1 0

diamonds are made with extreme intense heat and presser, they are not just made in the earth anymore, man has been able to re-create these conditions. true diamonds are now being made by man.

2006-08-21 03:32:45 · answer #9 · answered by crsstar 2 · 1 0

When I was in 2nd grade, there was a guy that came to our class that was telling us about stuff, and I remember him saying that diamonds come from compressed coal, that it takes many many many years for it to change to them.

2006-08-21 11:46:22 · answer #10 · answered by Punky Brewster 4 · 0 0

A build up of gasses under extreme heat and pressure. It's a chemical reaction

2006-08-21 03:15:52 · answer #11 · answered by Anonymous · 1 0

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