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How are rocks classified as igneous rocks?
Igneous rocks are generally classified first on the basis of theirformation (and therefore their texture) as intrusive or extrusive.Intrusive rocks are solidified from magma u…nder the surfaceresulting in a visible crystalline texture, and extrusive igneousrocks are solidified from lava at or near the surface, resulting ina small or nearly invisible crystalline texture. Igneous rock can additionally be classified by general chemistrycomposition as felsic, intermediate, mafic, and ultramafic. Felsicrocks are higher in silica and aluminum. Mafic rocks are higher inmagnesium and iron.
Igneous rocks are classified by their mineral composition and texture.
Extrusive igneous rocks.
If u are at a science class and do this for homework, I'm glad that I gave you then answer, it took me 10 minute to figure out It's Composition
Yes, by all three. They occupy a complicated sequence from "basic" (relatively low silica: basalt) to "acid" (high silica: granite), and are further complicated by local acce…ssory mineral content.
Igneous rocks are classified by either being intrusive or extrusive, then mafic or felsic then they are classified by either fine grain or course grained textures.
Texture and composition.
Igneous rocks are formed by the cooling of lava (above Earth's surface) or magma (below). Rocks in general are classified by their mineral composition, texture, and origin. Ig…neous rocks all have the origin of molten material, there are two categories within this: intrusive and extrusive. Intrusive rocks formed below earth's surface and extrusive rocks above. Their mineral composition varies greatly and depends on each individual rock. The classification of igneous rocks in texture is linked to their origin. The texture of a rock is defined by its grain: can you see and feel the little rocks that make it up? If you can, that rock has a coarse grain, if you can't see the bits, it is fine grained. Intrusive igneous rocks are usually fine grained; extrusive, coarse grained.
Granite and Andesite are two main factors of Igneous rock! Granite - Used for bench tops etc... And Andesite - Used for Walls and very strong things.
extrusive and intrusive OR plutonic and volcanic
The two major properties used to classify igneous rock are: Crystal Size/Texture--Small crystals are indicative of rapid above ground cooling of lava into what is classified …as extrusive igneous rock such as basalt, obsidian, or rhyolite. Large crystals are indicative of slow cooling magma underground, resulting in what is called intrusive igneous rock such as granite, gabbro, and diorite. Chemistry or Mineralogy--Igneous rock is also classified by its elemental composition. Igneous rock, whether intrusive or extrusive, that is high in silica is classified as felsic. Igneous rock that is low in silica, but higher in heavier elements like iron, is classified as mafic. Rocks falling between the two are classified as intermediate.
Geologists classify rocks by where they are formed; above ground or under ground
Intrusive and extrusive factors of an igneous rock classify them. The other factors are if they are vesicular, coarse, fine grained, glassy, or very coarse
Their texture and mineralogy.
Based on their method of formation.