Basalt is a very common igneous rock. In fact it is the most common rock in the Earth's crust. Almost all oceanic crust is made of basalt and basalt is a common in many volcanic regions around the world. Basalt comes from extensive lava flows. Basaltic rock that cools slowly in a large thick layer will often form a distinctive hexagonal prismatic figure. Basalt is usually grey to black in color.
Limestone rocks are sedimentary rocks that are made from the mineral calcite which comes from the beds of evaporated seas and lakes and from sea animal shells. This rock is commonly used in concrete and is an excellent building stone for humid or hot regions of the earth. Limestone ordinarily is white, but can appear in different colors and patterns due to impurities. Impurities of iron oxide give the rock brown, yellow or red color. Impurities of carbon can give it a blue, black or gray color. The texture of this stone can be coarse to fine.
Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone. It is composed primarily of calcium carbonate. Marble is commonly used for sculptures and as a building material. Marble is a rock resulting from metamorphism of sedimentary carbonate rocks also.
Granite rocks are igneous rocks which were formed by slowly cooling pockets of magma that were trapped beneath the earth's surface. This allows crystals of the four minerals to grow large enough to be easily seen by the naked eye. Granite is used for long lasting monuments and for trim and decoration on buildings. Granite is an igneous rock that is composed of four minerals. These minerals are quartz, feldspar, mica, and usually hornblende. Granites can be pink to gray in color, depending on their chemistry and what minerals it is made up of.
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