Answer:
Extrusive rocks Intrusive rocks · When molten magna comes out of the interior of the earth and cools down on its outer surface, the extrusive rocks are formed · These rocks are also known as volcanic rocks. · The lava cools quickly on the earth?s crust and leads to the formation of small crystals. · They contain a low percentage of Silica and a high percentage of oxides and are dense. · They break up into very fertile soils for example, basalt rock. · When molten magna cools, down slowly deep inside the earth?s crust then intrusive rocks are formed. · These rocks are also known as Plutonic rocks. · The slow rate of cooling produces large crystals. For example, granite. · Granite consists of 3 minerals- quartz feldspar and mica. · Granite is not very dense.
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