Skarn

As skarn a very heterogeneous group of metamorphic rocks ( rocks conversion ) is called, which result from reactions of acidic magmas with carbonate rocks.

Description of rock and mineral composition

A skarn is a fine-grained metamorphic rock usually green or red, but occasionally gray, black, brown or white color. The color of the Skarne may vary within a deposit. You can include as many as pyroxene calcium, magnesium and iron-rich silicate minerals, they are next to it quite rich in copper, lead, zinc and tungsten. In skarns is garnet, diopside, epidote and quartz, giving some garnet and diopside form large single crystals or may occur frequently. Furthermore, amphiboles, carbonates, fluorite and other rare minerals come grenade in different colors, Vesuvian, before.

Formation

Skarns occur only on a small scale. They are found within the contact zone of major igneous Intrusivgesteinskörpern, such as granites, with carbonate rocks such as dolomite or limestone. By starting from the magmatic melt and heat by highly enriched with elements of solutions that penetrate from the melt from the surrounding carbonate rocks, there chemical reactions are triggered that lead ores and the formation of silicate minerals ( metasomatism ). The ore minerals are mainly magnetite and sulfides.

Furthermore rarely occur skarns at the contact area of volcanic rocks.

Use

In economically recoverable deposits one also speaks of Skarnerzlagerstätten. Many skarns have been used by mining, if they lead economically exploitable mineral concentrations. The rare skarns but are used in the construction industry exclusive interior fitting also because of their interesting decor.