Pyrite
The pyrite was noticed the old ones for the spark S which it produces under the shocks, but also for its metal glare of a Jaune cold similar to that of the Laiton which sometimes made name it gold of insane the . Its name comes from the Greek πυρίτης ( λίθος ) - pyrítēs (líthos) - literally “stone with fire”.
It is a Sulfure of Fer running in the Nature. Of formula FeS2 . It belongs to the crystalline Système cubic, its crystals often takes dodecahedral forms with the pentagonal faces and sometimes impressive dimensions.
The pyrite was exploited like source of Soufre than of Fer. This polluting Industrie very tends however to being replaced by other processes.
Forty thousand years ago, the man developed a kind of Briquet made up of a pyrite and a Silex which sparked by percussion. Time often transformed the pyrite of this device into Limonite when one discovers some at the time of excavations.
The presence of pyrite in the mine S of coal is source of accidents: the sparks resulting from the shock of the metal tools with the pyrite can cause a Firedamp explosion.
Moreover, the pyrite is recognized as a harmful agent when it is found in the granualts being used for manufacture of the concrete. When the pyrite becomes active, it weakens the foundations of the buildings. It is thus important to make analyze its composition before the purchase of a property.
It is not used as source of iron for the manufacture of steel because it makes this last breakable. However the last processes of biolixiviation allowed the extraction of Chromium starting from the pyrite.
See too
Marcassite