diamond

Diamond in Greek means "unbreakable." Diamonds can only be scratched by diamond. A diamond's color is typically yellow brown or gray. Less often they can be found to be blue, green and black or even pink Many diamonds today are synthetically made from iron ore, but there is no detectible difference, and they are cheaper than naturally occuring diamond formations __** Basic Information **__ // Category- Native Minerals // // Chemical Formula- C // // Molar Mass- 12.01 g/mol // // Crystal Habit- Octahedral // // Crystal System- Isometric-Hexoctahedral (Cubic) // // Fracture- Conchoidal (shell-like) // // Streak- Colorless // // Density- 3.5-3.53 g/cm3 // // Refractive Index-2.418 (at 500nm) // Understanding the chemistry of a diamond requires a basic knowledge of the element carbon. A neutral carbon atom has 6 protons and 6 neutrons in its nucleus, balanced by 6 electrons. The electron shell configuration of carbon is 1s22s22p2. Carbon has a valence of 4, since 4 electrons can be accepted to fill the 2p orbital. Diamond is made up of repeating units of carbon atoms joined to four other carbon atoms via the strongest chemical linkage, covalent bonds. Each carbon atom is in a rigid tetrahedral network where it is equidistant from its neighboring carbon atoms. The structural unit of diamond consists of 8 atoms, fundamentally arranged in a cube. This network is very stable and rigid, which is why diamonds are so very hard and have a high melting point. Virtually all carbon on Earth comes from the stars. Studying the isotopic ratio of the carbon in a diamond makes it possible to trace the history of the carbon. For example, at the earth's surface the ratio of isotopes carbon-12 and carbon-13 is slightly different from that of star dust. Also, certain biological processes actively sort carbon isotopes according to mass, so the isotopic ratio of carbon that has been in living things is different from that of the Earth or the stars. Thus it is known that the carbon for most natural diamonds comes most recently from the mantle, but the carbon for a few diamonds is recycled carbon of microorganisms, formed into diamonds by the earth's crust via plate tectonics. Some minute diamonds that are generated by meteorites are from carbon available at the site of impact; some diamond crystals within meteorites are still fresh from the stars.
 * Diamond **
 * Start __with Carbon__**

__**Properties of Diamonds**__ Diamond is the hardest natural material. The Mohs hardness scale, on which diamond is a '10' and corundum (sapphire) is a '9', doesn't adequately attest to this incredible hardness, as diamond is exponentially harder than corundum. Diamond is also the least compressible and stiffest substance. It is an exceptional thermal conductor - 4 times better than copper - which gives significance to diamonds being called 'ice'. Diamond has an extremely low thermal expansion, is chemically inert with respect to most acids and alkalis, is transparent from the __far infrared__ through the deep ultraviolet, and is one of only a few materials with a negative work function (electron affinity). One consequence of the negative electron affinity is that diamonds repel water, but readily accept hydrocarbons such as wax or grease. Diamonds do not conduct electricity well, although some are semiconductors. Diamond can burn if subjected to a high temperature in the presence of oxygen. Diamond has a high specific gravity; it is amazingly dense given the low atomic weight of carbon. The brilliance and fire of a diamond are due to its high dispersion and high refractive index. Diamond has the highest reflectance and index of refraction of any transparent substances. Diamond gemstones are commonly clear or pale blue, but colored diamonds, called 'fancies', have been found in all the colors of the rainbow. Boron, which lends a bluish color, and nitrogen, which adds a yellow cast, are common trace impurities. Two volcanic rocks that may contain diamonds are kimberlite and lamproite. Diamond crystals frequently contain inclusions of other minerals, such as garnet or chromite. Many diamonds fluoresce blue to violet, sometimes strongly enough to be seen in daylight. Some blue-fluorescing diamonds phosphoresce yellow (glow in the dark in an afterglow reaction).

__** Chemical stability **__ Diamonds' chemical property is very stable. Under room temperature diamonds do not react with any chemical reagents including various kinds of acid and alkali. Diamonds' surface can only be oxidized a little by just a few oxidants under high temperature (below 1,000 °C). So acid and alkali can be used to refine synthetic diamonds. __**Diamonds, the symbol of love**__ Since diamonds are composed of a single element, they are the purest of all gemstones. Diamonds were discovered in India in 500 B.C., and the name "diamond" comes from the Greek word "Adamas" which means unconquerable - suggesting the eternity of love. Since ancient Greece, diamonds and diamond jewelry have been the traditional symbol of love, and the ancients believed they were hardened dew drops, splinters from the stars or crystallized lightning. Today, the gem-grade diamonds are used to make fine jewelry and engagement rings. The industrial-grade diamonds are used mainly for cutting and polishing. A diamond is the hardest substance known to humankind, and is made of a crystallized carbon that has unique powers of light reflection.

__**Diamond Color**__

Colorless and near-colorless diamonds are the most valuable. Though most diamonds may appear colorless to the naked eye, the majority of diamonds contain slight traces of yellow or light brown when viewed under a jeweler's loupe. Depending on the stone's size, a single increase in color grade can boost the value of a diamond by thousands of dollars per carat. A traditional engagement diamond is usually colorless or near-colorless. In nature, diamonds can also occur in shades of red, pink, blue, green and deep yellow - These are called "Fancy diamonds". In the United States and around the world colorless diamonds are graded on an alphabetical scale, introduced by the Gemological Institute of America (GIA). "Colorless" or "rare white" diamonds are of color grades D, E and F. Diamonds of color grade D are very rare, and extremely valuable.

__**Diamond Carot Weight**__ The weight of a diamond is measured in carats (ct.). Each carat is divided into 100 points. For example: 1ct.= 100 points, 1/2 ct. = 50 points, etc. The carat weight alone is almost meaningless unless you also consider the cut, clarity and color of the diamond. A large diamond is not very valuable if it lacks brilliance, purity and high-grade color. However, since larger stones are rarer than smaller ones, diamond value rises exponentially with carat weight. Therefore, a diamond weighing 3.0 carats, will always be worth more than three 1.0 carat stones of the same quality. No two diamonds are exactly alike, and you must weigh all of the factors - color, cut, clarity and carat weight - when making your diamond jewelry buying decision.

__**Formation**__ Diamonds are formed when carbon deposits are exposed to high pressure and high temperature for prolonged periods of time. Deep within the earth's crust there are regions that have a high enough temperature (900¼C to 1400¼C) and pressure (5 to 6 GPa) that it is thermodynamically possible for liquified carbon to form into diamonds. Under the continental crust, diamonds form at depths of between 60 miles (100 kilometers) and 120 miles (200 km), in the diamond-stable conditions defined by the "//graphite-diamond equilibrium boundary//." At these depths, pressure is roughly 5 gigapascals and the temperature is around 2,200 __degrees__ Fahrenheit (1,200 degrees Celsius). Diamond formation under oceanic crust takes place at greater depths due to lower surface temperatures. Therefore, diamond formation within the oceanic crust requires a higher pressure for formation. Long periods of exposure to these higher pressures and temperatures allow diamond crystals to grow larger than under land masses.

South Africa is the most Diamond-rich nation on earth. In 1867, the first South African diamond was discovered. After the course of the next 15 years, more diamonds had been extracted in South Africa than any other location on earth. Let it be known that more diamonds were discovered in this area in 15 years than had been found in India over a 2,000 year period. Brazil is also known for it's rich diamond deposits, but they have are fairly depleted as of today.
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iamond jewelry is among the most popular forms of jewelry. Commonly associated with romance, jewelry featuring diamonds is appreciated for its brilliance, style and meaning. Despite diamond jewelry's popularity and constant presence in our society, picking the right piece is not as simple as what many might assume. Confronted with the nuances of contemporary styles and budgeting, not to mention personal tastes, it's no wonder how diamond jewelry shoppers can feel overwhelmed when trying to find that perfect set of**__ [|wedding bands] __**, a ring or bracelet. As a result, Zales has prepared this Diamond Jewelry Buyers Guide to give you a sound understanding of what to look for when making a purchase. After all, buying diamond jewelry should be enjoyable! To maximize the pleasure of your purchasing experience, it's helpful to develop a broad understanding of diamond jewelry, which includes a brief history and the basic questions you should answer before beginning your shopping trip. Afterward let's look more closely at diamonds themselves with a review on the 4 Cs of diamond quality and conclude with a diamond jewelry glossary that will educate you on all the terms you need to know when researching your purchas