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2007-12-06 13:39:11 · 7 answers · asked by Uzma S 2 in Science & Mathematics ➔ Earth Sciences & Geology
Igneous rocks are classified by two things, first, the magma type, which depends on the amount of silica present. They are further classified by how big the crystals are. The crystal sizes are determined by how fast the magma cooled. Faster cooling equals small crystals, longer cooling equals larger crystals.
2007-12-06 15:57:59 · answer #1 · answered by mike h 3 · 1⤊ 0⤋
How Are Igneous Rocks Classified
2016-09-28 23:11:38 · answer #2 · answered by ? 4 · 0⤊ 0⤋
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On what basis are igneous rocks classified?
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2015-08-16 16:12:00 · answer #3 · answered by ? 1 · 0⤊ 0⤋
igneous rocks are directly formed from the cooling of magma
2007-12-06 13:42:52 · answer #4 · answered by 3.141592653589793238462643383279 3 · 0⤊ 1⤋
Either rapid cooling or slow cooling (determines size of crystals) and by presence or absence of silica; then by mineral types.
2007-12-06 15:47:53 · answer #5 · answered by Howard H 7 · 0⤊ 0⤋
The gross classification is based on manner of origin, how the stuff formed. How that is interpreted is based on physical and chemical make-up of the rock. textures and mineralogy are the primary criteria.
2016-03-13 13:57:03 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Chemistry (which affects mineralogy) and mechanism of formation (extrusive versus intrusive mode of formation), which affects granulometry (grain or mineral size).
2007-12-07 00:01:54 · answer #7 · answered by busterwasmycat 7 · 0⤊ 0⤋
They are classified as composition/texture or (size of crystals).
2015-02-10 11:55:26 · answer #8 · answered by ? 1 · 0⤊ 0⤋