Igneous rocks that are dense and dark-colored are called basaltic rocks. They are formed from magma that is rich in iron and magnesium and poor in silica content.
Basalt froms from basaltic lava is heavy, dark-colored, dense lava. Basaltic lava is dark because it contains high amounts of iron and magnesium.
The rock of the continental crust is mostly granitic in composition, meaning it is a high silicate intrusive igneous rock. The rock of the oceanic crust is basaltic in origin, meaning it is lower in silica and higher in heavier elements like iron and magnesium and is classified as a mafic igneous rock. Oceanic crust is therefore more dense than continental crust.
the lighter the rock the lower the density. the darker the rock, the higher the densit.
The oceanic crust is made out of basalts - (lava-hardened Iron/Magnesium Silicate mixtures which solidified rapidly).
A peridotite is a dense, coarse-grained igneous rock, consisting mostly of the minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica.
basaltic
Light-coloured igneous rocks, such as granite, have a higher silica content and lower iron and magnesium than darker ones, such as basalt. Since iron and magnesium are very dense minerals, this makes darker igneous rocks more dense than lighter ones.
Basalt froms from basaltic lava is heavy, dark-colored, dense lava. Basaltic lava is dark because it contains high amounts of iron and magnesium.
less dense
Normally, light colored igneous rocks are less dense compared to dark colored igneous rocks. This is because the light colored rocks have a less iron in them.
Igneous rocks are divided into four groups based on their composition (often determined by observing density and color).Felsic (also called Silicic) igneous rocks have a lower density, and are generally lighter in color (white, tan, pink). They have a higher silica content and a lower iron and magnesium content than the other types of rock. Granite and rhyolite are felsic igneous rocks.Intermediate igneous rocks have a density between felsic and mafic rocks. They have a high silica content and a medium iron and magnesium content. These rocks are usually gray or a similar, medium-toned color. Andesite and diorite are intermediate igneous rocks.Mafic igneous rocks are quite dense, and have a much higher iron and magnesium content than felsic or intermediate igneous rocks. Mafic rocks are usually black or blackish. Gabbro and basalt are mafic igneous rocks.Ultramafic igneous rocks are the densest type, and have the highest iron and magnesium content. Ultramafic rocks are usually (surprise!) green. Peridotite is an ultramafic igneous rock.
Light colored igneous rock is called felsic, and is high in quartz, muscovite mica, and orthoclase feldsparcontent. Dark colored igneous rock is called mafic, and contains a lesser amount of silica along with olivine, pyroxene, amphibole, biotite mica, and plagioclase feldspar.
Normally, light colored igneous rocks are less dense compared to dark colored igneous rocks. This is because the light colored rocks have a less iron in them.
The rock of the continental crust is mostly granitic in composition, meaning it is a high silicate intrusive igneous rock. The rock of the oceanic crust is basaltic in origin, meaning it is lower in silica and higher in heavier elements like iron and magnesium and is classified as a mafic igneous rock. Oceanic crust is therefore more dense than continental crust.
basaltic rocks are darker because they are more dence granitic rocks are less dence so they are lighter
the lighter the rock the lower the density. the darker the rock, the higher the densit.
It is made from a rock type known as Peridotite.Peridotite is an ultramafic dense, coarse-grained igneous rock consisting mostly of the minerals olivine and pyroxene containing less than 45% silica.