Silicate marble
Silicate marbles or Kalksilikatgesteine are of silicates prevailed limestones that a metamorphosis have undergone. There are three typical groups:
- Sand-lime bricks with detritic and non- detritic quartz components
- Marl-like metamorphic limestones with contents of anorthite , zoisite and grossluar , occasionally also phlogopite and Vesuvian
- Silicate dolomites with the participation of calcite , tremolite , talc minerals , forsterite and diopside .
In the structure of these rocks, the non-carbonate components are scattered or contained in layers. In the latter case, they can develop a special visual effect.
Silicate marbles sometimes show an interesting decor and are very rare stones. During the metamorphosis, the clay minerals and chlorite contained in the parent rocks react to form iron and calcium magnesium and form garnet , pyroxene , wollastonite and Vesuvian . Cipollino has green chlorite in its mineral inventory and Castione has red-brown garnets. Silicate marbles that contain garnets are sometimes called silicate garnet marbles.
According to modern petrographic points of view, the term silicate marble is rarely used, because the differentiation according to the content of silicate minerals in marbles does not seem sensible. Typically it was used for marbles with sandy or pelitic parts.
literature
- Wolfhard Wimmenauer: Petrography of igneous and metamorphic rocks . Enke, Stuttgart 1985, ISBN 3-432-94671-6
Natural stone types
- Castione , (Canton Ticino, Switzerland, near Bellinzona )
- Cipollino , ( Stazzema / Lucca , Italy)