Melaphyr
In German usage, melaphyr is a fine-grained rock, sometimes with a porphyry structure . The name is derived from the Greek µέλας mélas for "dark" and φύρω phìro for "blended, mixed".
Rock description
Like basalts and andesites, melaphyres usually have a dark hue, but some are colored reddish due to hematite . Some of them have a porphyry structure . They often have large cavities that are partially or completely filled with secondary minerals (" almond stones "). Today the stone is used almost exclusively for the production of paving stones . In the past, the almonds in the Melaphyr of the Nahe region ( Idar-Oberstein ) were an important supplier of agate . However, these deposits are largely exhausted.
Surname
The term melaphyr , applied to paleo - volcanic rocks, is limited in German to the current term basalts , which have a Permian age. In international usage, however, melaphyr is also used on basalts of non-Permian age. Nowadays, the term Melaphyr is only used in the combination Melaphyr-Mandelstein , otherwise Melaphyr is hardly used in Germany.
literature
- Dietmar Reinsch: Natural stone studies. An introduction for civil engineers, architects, preservationists and stonemasons. Enke, Stuttgart 1991, ISBN 3-432-99461-3 .
- Roland Vinx: Rock determination in the field. 2nd edition 2008 Springer-Verlag, Berlin / Heidelberg 2008, ISBN 978-3-8274-1925-5 .
Web links
- Melaphyr. Rock description at geodienst.de
- Melaphyr-Mandelstein Saar-Nahe. Melaphyr-Mandelstein from the Saar-Nahe area, supervision of polished rock surfaces, course geomaterials, Institute for Geosciences, Johann Wolfgang Goethe University Frankfurt am Main