Salary for Real Estate Brokers. Real estate brokers sell real estate for other individuals. They do this for a fee, also called a commission. Real estate brokers search other similar properties to compare prices and ensure the property is being listed at a competitive price. Brokers also monitor the fulfillment of the terms of the agreement once it is made and negotiate between buyers and sellers.
Oceanic crust is predominantly made of the rock basalt. Basalt is an extrusive igneous rock (meaning it forms once lava reaches the earth's surface... or ocean floor... and cools down). It is a dark colored, grey to black rock that has a lot of iron and magnesium in it, but not a lot of silicon.
In geologist's shorthand, oceanic crust is mafic while oceanic mantle is ultramafic. Oceanic crust, being so thin, is a very small fraction of the Earth - about 0.1 percent - but its life cycle serves to separate the contents of the upper mantle into a heavy residue and a lighter set of basaltic rocks.