Gold

Gold (of indogermanisch ghel: shining, (yellow)) a chemical

element and a precious metal in such a way specified are, the chemical

contraction outer one for gold are to latin designation Aurum to be

due. Gold consists of only a sturdy isotope. The heavy metal is soft

like tin and of remarkable coloredness. It is not attacked by acids

generally; an exception forms the acid mixture "aqua regia", a mixture

from hydrochloric acid and nitric acid. In aqueous cyanide solutions

gold is easily soluble under admission of oxygen as complex

connection. In sour hydrothermalen solutions gold is relatively

well physically soluble. The moreover one it separates easily in many

metals to alloys. Some the unusual characteristics like the

gold-yellow color and high ductility, can be explained after newer

computations best with the relativistic effect.

Gold for thousands of years for decoration and in the form of gold

coins as currency one uses.

 

Gold occurs in nature as mineral. It crystallized in the

cubic crystal system, has a hardness from 2,5 to 3, a deep color,

which admit accordingly as "gold-yellow" are, and identical line

color. In fine distribution it is depending upon grain size yellowish,

ocher-brown to magenta violet and as gold magenta is then designated.

With increasing temperature feingold at chroma loses and is

lightyellow glowing, before it melts. The melted metal is

lemon-yellow, easily greenish and receives its intensive yellow-orange

color only again if it is completely cooled down.

Admixtures of copper let appear reddish it pink or, lower the

fusing temperature and increase at the same time hardness, firmness

and polishing bar considerably. Rising silver portions

change the color of the pure gold over lightyellow after lightgreen

and finally too white; Fusing temperature and hardness change thereby

only very little. Most metals, so also the well-known

platinmetalle, mercury and the iron metals lead as admixtures

against it in rising portions to a decolorization in form of a rather

dirty-yellow-grey to grey-white alloy. They contribute at the same

time however also to a substantially larger hardness and firmness.

 

History

Gold ranks among the first metals, which were processed by

humans. This is on the one hand because of it that gold shows the

remarkable yellow color, very often gediegen, thus as element in

nature occurs and from ores to be chemically isolated does not only

have.

In addition gold can be worked on very well mechanically. The easy

alloyage bar with many metals, the moderate fusing

temperatures and the favorable characteristics of the alloys made gold

very attractive as material. Due to its coloredness, which became

corrosion resistance, for which is the basis for the stability of the

gloss, and rarity and remarkable weight, it in many cultures before

everything for ritual articles used. The gold production probably

began in the copper time. In Central Europe golden articles can be

proven for the second millenium before Christ. It was processed for

instance in the golden hat by boat operator city or the sky disk by

Nebra.

Since age ago gold was very desired in Europe, Asia and Africa. The

travel of the Argonauten to the golden fleece after Kolchis

represents the probably earliest documented far navigation of the

Greeks. Old person the will speaks of the golden calf, which the

Israeliten manufactured itself as Goetzenbild, while Moses

received the ten requirements, and of the gold country Ophir. Greed

for gold became the reason for wars and conquest courses. The

Egyptians exploited occurrences in Oberaegypten and Nubien. The

Romans for their part used find places in small Asia, Spain, Romania

and Germanien. The dream of the Alchemisten of the Middle Ages

was the production of gold.

Also in South America and Mesoamerika humans began already early

with the gold production and gold processing. Thus for example the

Mochica ordered at the beginning of the 1 in Peru already.

Millenium over a highly developed culture of the gold processing,

which included the alloy formation (Tumbago and gold plating). For

ritual purposes articles were manufactured by several kilograms of

gold.

The first gold finds in central and South America attracted European,

in particular Spanish conquerers, who destroyed the indigenen

cultures after the travels of Christoph Kolumbus and which gold

in Galeonen created to Europe. Spain became so temporary the

richest nation of Europe.

Gold finds again and again attracted large quantities of adventurers.

In 19. Century came it on different continents to gold fever mass

movements specified into the find areas of large gold quantities.

Examples are California gold fever in the year 1849 or gold fever 1897

at the Klondike River in Alaska. Also in Australia and South

Africa it came to gold fever. Hardly one the gold-looking for became

however rich by bergmaennischen gold dismantling or gold laundry.

Into the 1920er years tried the chemist Fritz Haber gold from sea

water to win. The average yield was however too small with 0,004

milligramm gold per ton of sea water for an economic utilization.

Also today the varying gold price often leads to social distortions:

Thus the falling gold price led to a strong depletion of the

population in Africa, who lives on gold production. In the Brazilian

Amazon area the informal gold dismantling is connected by

Garimpeiros often with serious social and ecological consequences.