Basalt is commonly very fine grained, and it is nearly impossible to see individual minerals without magnification. Basalt is considered a mafic silicate rock. Among other characteristics, mafic minerals and rocks are generally dark in color and high in specific gravity .
If olivine is present the rock is called olivine basalt. Microscopic examination show the groundmass to consist of plagioclase (usually labradorite), pyroxene, olivine and magnetite, with a wide range of accessory minerals.
a magmatic rock. Basalt consists predominantly of plagioclase (labradorite); also present are pyroxenes, olivine, magnetite, sphene, apatite, and other minerals. The chemical composition of basalt is close to gabbro which is its analogue in depth. Almost completely crystalline basalts are called dolerites.
Description of Minerals and Rocks. ... If the magma cools quickly, as lava or basalt does, the separate mineral grains are small. Igneous rocks are classified on the basis of the size and arrangement of the individual crystals and the kinds of minerals present (table 2).
basalt - the commonest type of solidified lava; a dense dark grey fine-grained igneous rock that is composed chiefly of plagioclase feldspar and pyroxene pyroxene - any of a group of crystalline silicate mineral common in igneous and metamorphic rocks
Basalt definition is - a dark gray to black dense to fine-grained igneous rock that consists of basic plagioclase, augite, and usually magnetite. a dark gray to black dense to fine-grained igneous rock that consists of basic plagioclase, augite, and usually magnetite… See the full definition.
Description. Andesite is a volcanic rock similar to basalt only lighter in color and containing less iron and magnesium than basalt. Often containing phenocrysts (large conspicuous crystals), Andesite is a host rock for Andesine, a precious gemstone.
Basalt definition gives information about the Formation of Basalt and its composition.The composition of Basalt can be further divided into mineral and compound content. The mineral content of Basalt rock includes Olivine, Plagioclase, Pyroxene and The compound content of Basalt rock includes Aluminium Oxide, CaO, Iron(III) Oxide, FeO ...
Basalt is not a mineral, because is can not be expressed in a definite chemical equation, nor does it have a definite crystal structure. Basalt is a hard, black volcanic rock with less than about 52 weight percent silica (SiO2). Common minerals in basalt include olivine, pyroxene, and plagioclase.
Basalt is a very common dark-colored volcanic rock composed of calcic plagioclase (usually labradorite), clinopyroxene and iron ore (titaniferous magnetite).Basalt may also contain olivine, quartz, hornblende, nepheline, orthopyroxene, etc. Basalt is a volcanic equivalent of gabbro.
'Instead there was just a headstone of black basalt.' 'This implies that individual primitive magmas are more likely to represent the composition of their individual mantle sources than more fractionated basalts.' 'Further, it is a common vesicle-filling mineral in basalts.'
Igneous rocks are classified by the minerals they contain. The main minerals in igneous rocks are hard, primary ones: feldspar, quartz, amphiboles, and pyroxenes (together called "dark minerals" by geologists), and olivine along with the softer mineral mica.
The Baynton basalt Description. Nine samples (B1-B9) were cut from a continuous but cracked 90-mm section of a core-stone and rind collected from a small road cut near Baynton, Victoria, Australia. This outcrop of the Newer Vol- canics of the Victorian Tertiary basalts was studied by Wilson (1978).
When flood basalts are forming above continents they fill rift valleys via giant fissures that split the continent. Magma migrates to the surface following these fissures, which are preserved as dikes.
Gabbro Gabbro is a dense, mafic intrusive rock. It generally occurs as batholiths and laccoliths and is often found along mid-ocean ridges or in ancient mountains composed of compressed and uplifted oceanic crust. Gabbro is the plutonic equivalent of basalt.
Basalt may be cut into thin slabs and used as monuments, building veneers or floor tiles. Dark in color, basalt rock is an igneous rock, which are (rocks produced under intense heat. Its dark color is partly as result of the minerals olivine and aspyroxene. Basalt rock …
The relative abundance of main rock types and minerals in the crust is shown in the Table. Texture. The texture of a rock is the size, shape, and arrangement of the grains (for sedimentary rocks) or crystals (for igneous and metamorphic rocks).
Basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in small intrusive bodies, such as an igneous dike or a thin sill.
By definition, basalt is an aphanitic igneous rock with less than 20% quartz and less than 10% feldspathoid by volume, and where at least 65% of the feldspar is in the form of plagioclase. Basalt is usually grey to black in colour, but rapidly weathers to brown or rust-red due to oxidation of its mafic minerals into rust.
Basalt is mainly made of two minerals: Plagioclase feldspar and pyroxene. Basalt has several textural varieties such as glassy, massive, porphyritic, vesicular, scoriaceous. Basalt has several textural varieties such as glassy, massive, porphyritic, vesicular, scoriaceous.
Basalt: Basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in colour, and comparatively rich in iron and magnesium. Some basalts are quite glassy (tachylytes), and many are very fine-grained and compact. It is more usual, however, for them to exhibit porphyritic structure, with
Basalt is a fine grained volcanic igneous rock formed of plagioclase and pyroxene minerals. It is most commonly formed by lava flow and in sills and dykes.Basalt is similar to gabbro in composition but the difference lies in the grain size of the two rocks.