Gold is a dense lustrous yellow precious metal element number 79 on the periodic table with the symbol Au. The symbol comes from the Latin name for gold – “Aurum”, which means "glow of sunrise". The word "Gold" comes from the Germanic languages, meaning "yellow/green". Gold has been known since prehistoric times and was one of the first metals to be worked, mainly because it was to be found as nuggets or as particles in the beds of streams.
Since ancient times, the gold mining industry of Europe has flourished in Cyprus, Greece and the Balkan Peninsula. The oldest European gold coins appeared from the territories of the Hellenic Empire.
- Gold is the only metal that is yellow or "golden". Other metals may develop a yellowish colour, but only after they have oxidized or reacted with other chemicals.
- Gold is extremely ductile. A single ounce of gold (about 28 grams) can be stretched into a gold thread 8 kilometres long. Gold threads can even be used as embroidery thread.
- Gold is the most malleable element. A single ounce of gold (~28 grams) can be beaten out into a sheet that is ~28 square meters. A sheet of gold can be made thin enough to be transparent. Very thin sheets of gold may appear blue because gold strongly reflects red and yellow.
- Gold metal flakes may be eaten in foods or drinks. Although gold is a heavy, dense metal, it is generally considered non-toxic.
- 24 karat gold is pure elemental gold. 18 karat gold is 75% pure gold. 14 karat gold is 58.5% pure gold, and 10 karat gold is 41.7% pure gold. The remaining portion of the metal usually is silver, but may consist of other metals or a combination of metals, such as platinum, copper, palladium, zinc, nickel, iron, and cadmium.
- In every cubic mile of sea water there is 25 tons of gold! That’s a total of about 10 billion tons of gold in the oceans; however, there’s no known way to economically recover it.
- Gold is a noble metal. It is relatively unreactive and resists degradation by air, moisture, or acidic. While acids dissolve most metals, just a special mixture of acids called "aqua regia" can be used to dissolve gold.
- High purity metallic gold is odourless and tasteless. This makes sense since the metal is unreactive. Metal ions are what confers flavour and odour to metallic elements and compounds.
All of the gold in the world that was ever mined could be compressed into a 16 meters cube.