Odenwald quartz
The Odenwald quartz was mined in quarries mainly on Borstein near the village of Reichenbach in the Odenwald on the Bergstrasse in the Odenwald . Today this quartz vein on Borstein is under nature protection. Further mining sites of this rock deposit are named Hohenstein and Katzenstein. There are a total of five main courses of this most colorful rock deposit, which is traded as natural stone in Germany . Odenwald quartz was formed between the Triassic and Tertiary around 30 million years ago.
Names
Because of the diversity of the Odenwald quartzite there are numerous trade names, either because of regional references as Reichenbacher-quartz and quartz Borstein or gesteinskundlich misnomers such as "Odenwald-quartzite", "Rose quartzite 'or' rose quartz named". An extremely dark brown type of Odenwald quartz, which was recently found near Balzenbach , formed partially pointed tooth-like textures and is called Odenwald Tigré .
geology
This quartz deposit occurs as vein quartz. It was made from barite ( barite ) in which later solutions of quartz penetrated and completely replaced it. This process is called metasomatosis . Odenwald quartz is a metasomatic quartz, the barite occurrence of which probably originated primarily in the Triassic and was secondarily converted in the Tertiary.
Occurrence
These are small, regionally limited occurrences. The five main courses in the Odenwald run from Auerbach via Reichenbach to Reichelsheim , Gronau to Knoden , Heppenheim and Fürth , Laudenbach to Rimbach and from Hemsbach to Mörlenbach .
The northern quartz deposit comes to the surface near Reichenbach am Borstein and Felsberg not far from the Hohenstein car park. The quarrying of this quartz deposit takes place in small-scale raw stones, which is why large-format objects cannot be produced. In the terrain, quartz veins are often exposed to the elements due to their hardness.
In addition to the five main corridors of this deposit, which are 5 to 30 meters wide, there are countless small and tiny corridors that have not undergone any transformation. The crystals of the five main courses have different colors, structures and degrees of conversion. Today only the northernmost corridor is of economic importance. Two quarries are being mined, the one at Katzenstein and one at Borstein .
Rock description
The components of Odenwald quartz are composed of 98 percent quartz and 2 percent opaque (non-transparent) minerals . The size of the quartz grains varies between 0.1 and 4 millimeters. Odenwald quartz has a high pore volume of around 10 percent, with cavities of 1 to 20 millimeters being the result of an imperfect metasomatosis . Odenwald quartz is chemically resistant and, due to its high quartz content, is one of the hardest hard stones that can almost only be processed mechanically and hardly by hand.
The color varies between brown to dark brown, light brown, yellowish red, reddish yellow, reddish yellowish, greenish and bluish. The changes in color of the rock, with the exception of greenish and bluish, result from the different enrichments of ore minerals. Yellow and red colors are caused by the addition of iron minerals, whereas the yellow and brown rock variants are caused by the mineral limonite present in the original rocks . In the boron stone deposits, the relatively rare green color occurs in the rock, which consists of malachite and the blue color is caused by azurite . Both minerals belong to the carbonate class .
Odenwald quartz is one of the most colorful rocks. Its texture is grainy in a directionless manner and there are stem-like structures, which in most cases give the impression of a parallel structure.
- Color variants of the Odenwald quartz
Pattern: Odenwald quartz red (8 × 6 cm). Polished surface
Pattern: Odenwald quartz brown (10 × 8 cm). Polished surface
Odenwald quartzite: red, brown, green in a pattern (10 × 8 cm). Polished surface
Pattern: Odenwald quartz (9 × 12 cm). Rough-sawn surface
use
Odenwald quartz is highly weather-resistant, frost-resistant and can be polished. When used as natural stone, the open pores are often filled. The polish hardly shrinks even over long periods of time. This quartz was mainly used nationally for gravestones, millstones, garden designs and regionally for natural stone masonry . Gravestones made of Odenwald quartz are very often found as isolated small gravestones in German cemeteries, numerous examples can be found in the Schenklengsfeld cemetery near Bad Hersfeld . According to a quarry operator, rough blocks of a maximum of 5 m³ can be extracted in individual cases and stone lengths of up to 1.80 m are possible.
Odenwald quartz used to be exported to the Benelux countries .
Web links
- Excursion report of the University of Frankfurt to the Odenwald from June 18, 2005 (PDF; 4.3 MB) by Andreas G. Neuhauser
- Image of a quarry for Odenwald quartz
- Operation for the mining of Odenwald quartz
literature
- Wolf-Dieter Grimm: picture atlas of important monument rocks of the Federal Republic of Germany. Edited by the Bavarian State Office for Monument Preservation. Lipp-Verlag, Munich 1990, ISBN 3-87490-535-7
- Friedrich Müller (Ed.): INSK - International Natural Stone Index. 10 vol., Ebner-Verlag, Ulm 1993, sheet 10.6.15 to 10.6.17
Individual evidence
- ↑ a b c d e f Müller: Natural stone index (see literature)
- ↑ a b c Information from a quarry operator ( memento of March 10, 2005 in the Internet Archive ). Retrieved July 7, 2010
- ↑ a b Grimm: memorial stones. Rock no.050 (see literature)
Coordinates: 49 ° 42 ′ 44.8 " N , 8 ° 41 ′ 1.2" E