Fruchtschiefer

Fruit shale are Kontaktmetamorphite which have emerged from shales.

Formation and mineral composition

They occur even at very low pressures ( niedrigmetamorphe rocks ) and at temperatures of about 500 ° C. At this temperature, cordierite developed to the grain size, which affected names formative. For mineral constituents include cordierite, muscovite, K-feldspar, quartz, biotite and hornblende.

Occurrence

Fruit shale occur in Germany as kontaktmetamorphes rocks in the Harz, the Ore Mountains, the Odenwald and Vogtland. In the known deposits are the deposits at Theuma and Tirpersdorf from the Ordovician. Their material has a widespread application on its region and beyond found.

Use

The traditional main application is in the form of gap rough masonry products of various kinds The Theumaer fruit shale is used further cleaved or polished as a facade panel and base blanking. Among the architectural components are also windows and door jambs, columns and steps. Chance occur also artistic and sculptural applications. From the Theumaer fruit slate one produced earlier locks and Well covers and containers for galvanic baths and acids.

The application of Theumaer fruit shale can be traced back to the Middle Ages. One example disks in the dating from the 14th century crypt of St. John's Church ( 1122) of Plauen.