Epidote from Dom Basilio, Bahia, Brazil.

The minerals epidote group consists of a number sorosilicaten, of which the most important is the mineral epidote. The mineral epidote is a calcium-iron-aluminum-silicate with the chemical formula Ca2 (Fe3 +, Al) Al2 (SiO4) (Si2O7) O (OH).The yellow-green to brown, gray or black epidote has a glass sheen, a gray-white stripe color and cleavage is perfect according kristalvlal [001]. The crystal system is monoclinic. The average density is 3.45 and the hardness is 7. Epidoot is not radioactive. The name is derived from the Greek epidote epidosis, which means "addition". Epidoot is a very common mineral worldwide, in particular in contact metamorphic rocks. It is formed in crystalline limestone and shale. Especially nice epidootkristallen be found in Handsome wall, at the Großvenediger in Untersulzbachthal, Salzburg (Austria). Epidote is common in the sand fraction of Dutch Quaternary river sediments. The heavy mineral analysis as in the Netherlands at the Geological Survey took place during the second half of the twentieth century, the mineral is classified among the so-called unstable group

 
Epidote