Study about gold
Gold is relatively rare chemical element. 1 million tons of soil contains approximately 5 kg of pure gold. Gold can't be eqnally found in the earth's crust as it forms very few but quite rich deposits. It is estimated that a cube of the edge length of 10 metres could be made from all the gold that is now in the world. Gold has a very characteristic yellow hue. It is uniquely malleable and ductile – one ounce (about 30 g) of pure gold can be beaten up to a tin plate of 30m3 of area. Gold is as hard as lead. It can easily be cut with a knife. It is a very good conductor of electricity and since it doesn't corrode it is often used to coat the electrical contacts. Gold reflects the warm infra – red radiation very well. The purity of gold is described in carates. Pure gold has 24 carats.
The world oceans contain milliards of pure gold, which can be found in different places in too few concentrations to have any practical meaning. Only a few grams o gold can be extracted from 1 million tons of sea-water. This metal is abtained only from its deposits. The easiest method to obtain gold is its scouring. The opencast method depends on mining gold directly from rich deposits of local gold and its minerals.
|
Name
|
Gold |
|
Latin name |
Aurum
|
|
Symbol |
AU |
|
Atomic number |
79 |
|
Atomic mass |
196,967 |
|
Melting point |
1064,4ºC |
|
Boiling point |
2808ºC |
|
Specific gravity |
19,3 (20ºC) |
|
Oxidization level
|
I, III |
Glitter of divine gold
Man's fascination of gold is as old as mankind itself. The ancient summers knew gold and appreciated it. The first know jewellery was made by the mysterious Etruscans. The builders of Egyptian Pyramids and obelisks put gold on their tops to pay homage to their god of the sun RA. In the Orient countries gold was the gods and rulers attribute. Special characteristics were attributed to amulets made of gold – they were strength, the owner's position, extra energy and confidence. The tradition of gold decorations and offering gold in token of respect and love – passing different historical windings exists up to now.
Gold has always been a wonderful metal, around which there orginated many legends, became the sourse of metaphors, proverbs and comparisons. There hasn't been an epoch indifferent to the glitter and price of gold. People inherited the worship of this metal from their ancestors. It was the basic measurer of value, the measurer of welfare, the aim of dreams and the way for forgers to lead an easy life.
Golden jewellery
Gold is a pure element (24 carats) which, in fact, doesn't exist in its pure form in jewellery. 18 – carat jewellery contains 75% of gold and 25% of silver and capper. These „other metals” are precisely determined in the hallmark law so not everything can be mixed with gold as all goods would lose their value. That's why the world has made an agreement that jeweller's articles can be of 23, 21, 18, 14, 12, 10, 9, 8 carats. In an 8 – carat article there is only 33,3 % of pure gold.
Gold in industry
Because of its characteristics pure gold is used in electroplating – to gilt particularly important parts,in electrotechnical industries, where it is used as the anti arroscive layer, to decorative gilt in watch – making, jeweller's and goldsmithing industries (for example: watch envelopes, goods of religious cult and jewellery). In the form of gold foil called gold – leaf, it is used mainly in conservators' studios to renovate works of art. antique interiors or precious picture – frames. In the form of paint gold is used to paint on porcelain and glass. Besides gold is used to make alloys, among which most frequent are the alloys of gold and copper or gold, copper and silver. This ones are used in jeweller's and goldsmith's goods. The alloys of gold and copper are used to coin. Lately gold has been used i modern jet / racket technics and in electronics.
Gold ....................
The percentage of gold contents in the earth's crust is very small, as it is the amount of 0,000001% of all the elements etering into the composition of the earth structure. In order to compare the above values you should know that the contents of other metals in the earth's crust is as follows – aluminium 7%, iron 5%, limestone and sodium – both 3%, magnesium – 2%. A Russian scientist „Fersman” calculated that in the earth's crust up to the depth of 1000 metres there are resources of 5 million tons. Until 1972 gold mining was limited because of the maintaining of constant rate of a dollar, that was 35$ for an ounce (troy ounce = 31,1 g which is about 1,12$ for 1 gram). At present the official price of gold at the stock Exchange fluctnates withinthe range of 300 – 400$ for 1 ounce, which means that in a few years the price of gold increased 10 times and in 1978 it reached the value of 800$ for an ounce. In Poland gold was mined – at the beginning of the 1950's – in Złoty Stok near Kłodzko, while mining arenic ores, and the annual profit fluctuated within the range of 30 – 50 kg. In the Middle Ages Złoty Stok was one of the biggest gold mines in Europe. Nowadays there is the only museum in Poland showing the technics and ways of gold mining in those times. The names of other localities such as Złotogóra or Złotoryja, indicate that gold was olso mined there.
Gold can be found in nature in its natural form as nugget or i the form of chemical compounds mainly with tellurium. In the natural form it exist as slugs or granulated, as so – called gold sand. Gold is often among some metal ores such as pyrite – iron bisulphide or arsenic pyrite – arsenic sulphide. The biggest nuggest so ever was found in the mines of New South Wales and weighted 236 kg.
