Gold on Postage Stamps
Gold
Symbol - Au - Crystallizes in the cubic system. hardness 2.5-3 , density 15.5-19.3; color from golden yellow to whitish (when there is a high proportion of silver); metallic sheen, yellow-gold or silver powder.
Occurences
This mineral forms in hydrothermal veins of high-temperature igneous rocks (quartz veins). It is also found in deposits of hydrothermal sulphides formed under high temperature. Most gold, ihowevers, is obtained from secondary concentrations of sedimentary origin (placers).
Important fields
The main gold-bearing districts are those of the Witwatersrand (South Africa), Mother Lode (California) Yukon (Alaska), Porcupine (Canada) and Russia.
The best collection of samples from both these places come from other areas is not economically important.
In Italy
The best known deposits are those in Pestarena Anzasca and Brusson in Valle del Lys, which are part of a modest district around the Monte Rosa.
Uses
Is the main commercial source of the metal, mainly used in jewelry, in dentistry, scientific instruments and electronic equipment and as a monetary base.
This is the reason why gold is considered a universal equivalent.
Gold Images
see also:
http://geostamps.eu
http://www.diamondstamps.eu - http://www.mineralstamps.eu