A dark, fine-grained igneous rock; diabase. It is extremely hard and tough and is commonly quarried for crushed stone, under the name of trap. It is a medium grained igneous rock, and can be dark grey or black with greenish shades in colour. (Geological Science) a dark basic intrusive igneous rock consisting of plagioclase feldspar and a pyroxene, such as augite; often emplaced in dykes 2. (Geological Science) any dark igneous rock whose composition cannot be determined with the naked eye It is a mafic rock, containing magnesium and iron, often in form of olivine. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. Dolerite is a dark igneous rock. Like other mafic rocks, it is relatively low in silica content. Reportedly, this field, home to "the largest diabase (, The Totem is 50m high x 4m wide and is the only freestanding, Our voyage took us near a noisy colony of guillemots, early arrivals on the black, Stonehenge consists of two kinds of stone: sarsen (Tertiary sandstone) and bluestone (various grades of, Five quarries extracted iron ore, limestone, sandstone, coal and, The soils, more than eight feet deep in most parts of the estate, are derived from reddish-brown, Both seams are thick seams of up to 6 meters thick with no faulting or, "Good examples of this include the excellent work undertaken by our geology team in conjunction with external consultants and the CSIRO in identifying the fractionated, Dictionary, Encyclopedia and Thesaurus - The Free Dictionary, the webmaster's page for free fun content. 1. Dolerite is similar in composition to basalt, which is eruptive (from volcanoes), and gabbro, which is plutonic. https://www.thefreedictionary.com/dolerite. any of various dark igneous rocks of basaltic composition, as diabase. a dark basic intrusive igneous rock consisting of plagioclase feldspar and a pyroxene, such as augite; often emplaced in dykes any dark igneous rock whose composition cannot be determined with the naked eye Derived forms of dolerite doleritic … The differing crystal sizes are due to the different rate of cooling, basalt cools quickly and has a very fine structure, while gabbro cools very slowly, at great depth, and large crystals develop. Diabase, also called Dolerite, fine- to medium-grained, dark gray to black intrusive igneous rock. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. Although not popular, it makes an excellent monumental stone and is one of the dark-coloured rocks commercially known as black granite.