Diamonds are a mineral

Diamonds are a mineral, a natural crystalline substance, the transparent form of pure carbon or nearly pure carbon. Diamonds have extraordinary qualities. Diamonds have a broad colour range, high refraction, high dispersion of fire, very low reactivity to chemicals, rarity, and of course, extreme hardness and durability. Diamonds are known as the "king of gems" they glitter, dazzle, and symbolize purity and strength.

A diamond is the oldest thing you will ever own, probably 3 billion years in age, fully two thirds the age of the Earth. A diamond is a strategic and high-tech supermaterial for our technological society. Diamond is the birth stone for the month of April.

A diamond is composed of the single element carbon, and it is the arrangement of the C atoms in the lattice that give a diamond its amazing properties. Both diamond and graphite are composed of just carbon. However a diamond is the hardest known material and graphite is one of the softest, this was caused by a rearrangement of the way the atoms are bonded together. Diamond carbon atoms are linked in a regular three-dimensional lattice with a repeating or crystalline pattern.
Diamond belongs to the cubic, or 'isometric' crystal system. The most commonly seen crystal structures or arrangements are:
• Octahedron (8 faces)
• Cube (6 faces)
• Dodecahedron (12 faces)
A diamond is the ultimate gemstone, having few weaknesses and many strengths. It is well known that diamonds are the hardest substance found in nature, but few people realize that diamonds are four times harder than the next hardest natural mineral, corundum - sapphires and rubies.

Natural diamonds are classified by the type and level of impurities found within them.
• Type Ia diamond - Most natural diamonds are of this type, which contain up to 0.3% nitrogen.
• Type Ib diamond - Very rare (~0.1%) in nature, but almost all synthetic (industrial) diamonds are of this type. They contain nitrogen at concentrations of up to 500 ppm.
• Type IIa diamond - Very rare in nature, these diamonds contain so little nitrogen that it can't be easily detected by the usual IR or UV absorption measurements.
• Type IIb diamond - Extremely rare in nature. These have such a low concentration of nitrogen (even lower than type IIa) that the crystal is a p-type semiconductor (due to uncompensated B acceptor impurities).

Silver

Silver is a chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold (electrum) and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc refining.
Silver has been known since ancient times and has long been valued as a precious metal, used to make ornaments, jewelry, high-value tableware, utensils (hence the term silverware), and currency coins. Today, silver metal is used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions. Its compounds are used in photographic film and dilute solutions of silver nitrate and other silver compounds are used as disinfectants. Although the antimicrobial uses of silver have largely been supplanted by the use of antibiotics, further research into its clinical potential is in progress.

Pearls

A pearl is a hard, general spherical object produced within the soft tissue (specifically the mantle) of a living shelled mollusk. Just like the shell of a mollusk, a pearl is made up of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes of pearls (baroque pearls) occur. The finest quality natural pearls have been highly valued as gemstones and objects of beauty for many centuries, and because of this, the word pearl has become a metaphor for something very rare, very fine, very admirable, and very valuable.

Valuable pearls occur in the wild, but they are very rare. Cultured or farmed pearls make up the majority of those that are currently sold. Pearls from the sea are valued more highly than freshwater pearls. Imitation or fake pearls are also widely sold in inexpensive jewelry, but the quality of their iridescence is usually very poor - and generally speaking, artificial pearls are easily distinguished from genuine pearls. Pearls have been harvested and cultivated primarily for use in jewelry, but in the past they were also stitched onto lavish clothing. Pearls have also been crushed and used in cosmetics, medicines, or in paint formulations.
Pearls that are considered to be of gemstone quality are almost always nacreous and iridescent, like the interior of the shell that produces them. However, almost all species of shelled mollusks are capable of producing calcareous concretions, creating pearls of lesser shine or less spherical shape. Although these may also be legitimately referred to as "pearls" under U. S. Federal Trade Commission rules, and are formed in the same way, most of them have no value, except as curios.

Diamond

In mineralogy, diamond (from the ancient Greek adámas, meaning "proper" or "unalterable") is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is the second most stable form of carbon, after graphite; however, the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is specifically renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material synthesized so far. Those properties determine the major industrial application of diamond in cutting and polishing tools.
Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with the wide transparency, this results in clear, colorless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green, purple, pink, orange or red. Diamond also has relatively high optical dispersion, that is ability to disperse light of different colors, which results in its characteristic luster. Excellent optical and mechanical properties, combined with efficient marketing, make diamond the most popular gemstone.
Most natural diamonds are formed at high-pressure high-temperature conditions existing at depths of 140 to 190 kilometers (87 to 120 mi) in the Earth mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years, which respectively corresponds to roughly 25% and 75% of the age of the Earth. Diamonds are brought close to the Earth surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites. Diamonds can also be produced synthetically in a high-pressure high-temperature process which approximately simulates the conditions in the Earth mantle. An alternative, and completely different growth technique is chemical vapor deposition. Several non-diamond materials, which include cubic zirconia and silicon carbide and are often called diamond simulants, resemble diamond in appearance and many properties. Special gemological techniques have been specially developed to distinguish natural and synthetic diamonds and diamond simulants.

GemStone

A gemstone or gem (also called a precious or semi-precious stone) is a piece of attractive mineral, which—when cut and polished—is used to make jewelry or other adornments. However certain rocks, and organic materials are not minerals, but are still used for jewelry, and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their lustre or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone.
Gemstones are identified by gemologists, who describe gems and their characteristics using technical terminology specific to the field of gemology. The first characteristic a gemologist uses to identify a gemstone is its chemical composition. For example, diamonds are made of carbon (C) and rubies of aluminium oxide (Al2O3). Next, many gems are crystals which are classified by their crystal system such as cubic or trigonal or monoclinic. Another term used is habit, the form the gem is usually found in. For example diamonds, which have a cubic crystal system, are often found as octahedrons.
Gemstones are classified into different groups, species, and varieties. For example, ruby is the red variety of the species corundum, while any other color of corundum is considered sapphire. Emerald (green), aquamarine (blue), bixbite (red), goshenite (colorless), heliodor (yellow), and morganite (pink) are all varieties of the mineral species beryl.
Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture, and luster. They may exhibit pleochroism or double refraction. They may have luminescence and a distinctive absorption spectrum.
Material or flaws within a stone may be present as inclusions.

Gold

Gold is a chemical element with the symbol Au and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. It is one of the coinage metals and formed the basis for the gold standard used before the collapse of the Bretton Woods system in 1971.

At the end of 2006, it was estimated that all the gold ever mined totaled 158,000 tonnes. This can be represented by a cube with an edge length of just 20.2 meters. Modern industrial uses include dentistry and electronics, where gold has traditionally found use because of its good resistance to oxidative corrosion and excellent quality as a conductor of electricity.

Chemically, gold is a transition metal and can form trivalent and univalent cations upon solvation. Compared with other metals, pure gold is more chemically unreactive, but it is attacked by aqua regia (a mixture of acids), forming chloroauric acid, and by alkaline solutions of cyanide but not by single acids such as hydrochloric, nitric or sulfuric acids. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Since gold is insoluble in nitric acid which will dissolve silver and base metals, this is exploited as the basis of the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test", referring to a gold standard test for genuine value.

The color of pure gold is metallic yellow. Gold, caesium and copper are the only metallic elements with a natural color other than gray or white. The usual gray color of metals depends on their "electron sea" that is capable of absorbing and re-emitting photons over a wide range of frequencies. Gold reacts differently, depending on subtle relativistic effects that affect the orbitals around gold atoms.
Common colored gold alloys such as rose gold can be created by the addition of various amounts of copper and silver, as indicated in the diagram above. Alloys containing palladium or nickel are also important in commercial jewelry as these produce white gold alloys. Less commonly, addition of manganese, aluminium, iron, indium and other elements can produce more unusual colors of gold for various applications.