Is a dark, intrusive igneous rock with a porphyritc or glassy structure and stream-lined and omnidirectional texture. It is fine-grained and its colour varies from gray-and-black to black. It contains pyroxenes (augit, titanium augit), plagioclases (labradorithe – anorthite) and olivine.
Is a deep-seated igneous rock that contains a number of potassium feldspars, acid plagioclases and quartz. Its colour is blue-tinted grey or red (rapakivi).
Is a compact sedimentary rock of white or grey colour, but sometimes with another tinge depending upon the presence of alloys.
Is a rock (crystallic calcite) that contains more than 95% of calcite. Originally white marble is stained with clay, various minerals (graphite, limonite, hematite and others) and organic compounds.
Is a chalcedony variety, bearing resemblance to agate. It has straight strips of color in brown, white or black-and-white. Black onyx with green chrysoprase and cornelian is chromatic chalcedony.
(Is a metamorphous rock of regional origin with fine to moderate granularity. For its prevailing span of colours (white to grey), it is often replaceable with marble.
Is a sedimentary semimetamorphosed fine-grained rock formed from claystone and siltstone, rocks containing the minerals black mica, muscovite and andalusite. Slate varies in colour from black to grey and has fine plane cleavage.
Is a chemical sedimentary rock with identical composition of calcite, but it differs from calcite in porosity. It may also contain clay and classic quartzite, and fossil remnants.
General information