Gold is a rare metallic element with a melting point of 1064 degrees centigrade and a boiling point of 2808 degrees centigrade. Its chemical symbol, Au, is short for the Latin word for gold, ‘Aurum’, which literally means ‘Glowing Dawn’. It has several properties that have made it very useful to mankind over the years, notably its excellent conductive properties and its inability to react with water or oxygen.
This stems back to ancient times in the Mediterranean /Middle East, when a carat became used as a measure of the purity of gold alloys (see next Question 5). The purity of gold is now measured also in terms of fineness, i.e parts per thousand. Thus 22 carat is 22/24th of 1000 parts = 916 fineness.
A Carat (Karat in USA & Germany) was originally a unit of mass (weight) based on the Carob seed or bean used by ancient merchants in the Middle East. The Carob seed is from the Carob or locust bean tree. The carat is still used as such for the weight of gem stones (1 carat is about 200 mg). For gold, it has come to be used for measuring the purity of gold where pure gold is defined as 24 carats.
The gold-containing ore has to be dug from the surface or blasted from the rock face underground. This is then hauled to the surface and milled to release the gold. The gold is then separated from the rock (gangue) by techniques such as flotation, smelted to a gold-rich Dore and cast into bars. These are then refined to gold bars by the Miller chlorination process to a purity of 99.5%. If higher purity is needed or platinum group metal contaminants are present, this gold is further refined by the Who l will electrolytic process to 99.9% purity. Mine tailings containing low amounts of gold may be treated with cyanide to dissolve the gold and this is then extracted by the carbon in pulp technique before smelting and refining.
All metal atoms are made of the same building blocks of protons, neutrons and electrons, but in different quantities, so in theory it could be possible to change base metals into gold or any other metal of value to mankind. In practice, it is achieved only in nuclear reactions, where heavy radioactive metals decay into other lighter elements, including some isotopes of gold. However, man’s ancient dream of turning base metals into gold is not a practical proposition. So it remains a dream!
Gold is traditionally weighed in Troy Ounces (31.1035 grams). With the density of gold at 19.32 g/cm3, a troy ounce of gold would have a volume of 1.64 cm3. A tone of gold would therefore have a volume of 51, 760 cm3, which would be equivalent to a cube of side 37.27cm (Approx. 1′ 3”).
The word gold appears to be derived from the Indo-European root ‘yellow’, reflecting one of the most obvious properties of gold. This is reflected in the similarities of the word gold in various languages: Gold (English), Gold(German), Guld (Danish), Gulden (Dutch), Goud (Afrikaans), Gull (Norwegian) and Kulta (Finnish).
If we take national gold reserves, then most gold is owned by the USA followed by Germany and the IMF. If we include jewellery ownership, then India is the largest repository of gold in terms of total gold within the national boundaries. In terms of personal ownership, it is not known who owns the most, but is possibly a member of a ruling royal family in the East.
Gold is made into a large number of different bars of different weights. The most well known are the large ‘London Good Delivery Bars’ which are traded internationally. These weigh about 400 Troy Ounces, i.e. 12.5 kg/ 27 lbs. Each. Others are denominated in kilogram’s, grams, troy ounces, etc. In grams, bars range from 1 g up to 10 kg. In troy oz, from 1/10 tr.oz. up to 400 tr.oz.. Other bars include tola bars and Tael bars.
If we make all the gold ever produced into a thin wire of 5 microns (millionths of a meter) diameter – the finest one can draw a gold wire, then all the gold would stretch around the circumference of the world an astounding 72 million times approximately!
A diamond is a crystal made up entirely of carbon atoms that are arranged in an isometric, or cubic, matrix. A cubic crystal arrangement is one in which the crystal essentially expands outward at the same rate in all directions during its initial growth; the ideal result, when the crystal forms without any interference, is a pure and perfectly formed octahedral shape.
Diamonds are made up of pure carbon atoms that exist deep in the ground, exposed to intense heat and pressure over billions of years. Over time, this pressure builds up and forces the diamonds and rocks up toward the surface in a volcanic-like explosion. The explosion creates a very deep, wide hole called a “pipe” into which most of the diamonds settle; these deposits of diamonds are known as primary deposits. Other diamonds are washed away by water or erosion, and often settle into the coastal waters of nearby bodies of water; these are alluvial deposits. These deposits occur in many places around the globe; however, the largest commercial deposits exist in Angola, Australia, Botswana, Namibia, South Africa, Russia and Zaire, which produce 80% of the world’s diamonds.
A newly mined rough diamond looks more like a piece of glass washed up on the beach than like the polished gems sold in jewelry stores. Bringing out their beauty requires the skill and art of a trained diamond cutter.
The “Ideal Cut” is a cut based on a specific set of proportions for a round brilliant diamond proposed by gem cutter Marcel Tolkowsky in 1919. While Tolkowsky’s original theories presented only one particular combination of proportions for creating the best balance of brilliance and dispersion, today the American Gemological Society recognizes any diamond falling within a narrow range of proportions and finish quality as being an “Ideal Cut” (also called an “AGS 0” or “AGS triple zero”).
Finding the rough diamonds is only the first step. Once diamonds have been mined and processed out of the ‘overburden’ (that is, the kimberlite rocks in which they are imbedded), the rough crystals are sorted and categorized according to their size, color, shape and other characteristics. At this point, a diamond can follow one of two routes.