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Synonyms: Nero Porto Rosa, NDG 048, Port Rose, Porta Rosa, Portarosa, Porto Rosa, Porto Rose, Portorosa, Portrose, Rosa Porto
Location: Portorose granite is quarried at quarry RN 000149, Fazenda Catumbi, Campos Gerais, Minas Gerais, Brazil. Do note that the spread of texture of Portorose is very wide and a small sample is mostly not representative.
Description: Portorose granite is a black migmatite with small, white, strong folded quartz and pink feldspar bands. This stone internationally may be nominated as a granite and in the area of application of the European Standard this stone must be nominated as a granite.
The veining and colour varies considerably and a small sample of Portorose granite may not be representative of the whole slab therefore swatch samples must be approved for large projects to ensure that the blocks are all extracted from the same quarry face for matching purposes. Ideal for both interior and exterior use, Portorose granite is frost free and polish constant.
Mineral Composition: Quartz: 30%, Microcline: 25%, Plagioclase: 20%, Biotite: 20%, Muscovite: 5%
Migmatite: A rock at the frontier between igneous and metamorphic rocks. They can also be known as diatexite. In many cases the darker part of the rock, consisting of biotite mica and hornblende, has been intruded by veins of lighter rock consisting of quartz and feldspar. A rock composed of a metamorphic (altered) host material that is streaked or veined with granite rock; the name means "mixed rock". Such rocks are usually gneissic (banded) and felsic rather than mafic in composition.