Silver
It is found in nature to the crystallized metallic state in the monometric system, but commonly in sheets, filaments, grains and nuggets in Canada, Peru and in Norway, while arranged under shape of the layers in Mexico and South America. We do not forget that also in Italy and just in the Sardegna region, the silver is found under shape of argentiferous galena (solfuro of silver lead) argentite (solfuro).
PHYSICAL PROPERTY OF SILVER
The pure silver is piu' the white man and the piu' shining of the metals. Unalterable, if to normal pressure, it gives place to silver oxide little if this comes increased, also. Its blackening has had to the formation of solfuro of silver for the presence, also of traces, solfidrico acid that are found easy in the air. In chlorine presence violacea coloration gives to place to silver chloride assuming in presence of the light one gray. It is melted with facility in the nitric acid, from which then the pure silver nitrate is gained. It comes endured after the gold for the malleability degree. E' the much less dense one of the gold, its specific weight is 10,500. It fuses easy to 961° degrees and volatilizza. Point of boiling is 1955° degrees. The hardness is: 2 ½ - 3. It comes used in alloy with other metals for conferirgli the hardness demanded for coins, or other objects put down which, coffee sets, ornaments, church furnishingses etc… Ordinarily in the proportion of 4/5 of silver and 1/5 of branch (800/1000) or (925/1000).