GENERAL GEOLOGY

Detailed explanation-1: -We generally find metallic minerals in igneous rocks. Iron, nickel, chromites and platinum are some of the examples of minerals that are found in igneous rocks. Q. Sometimes igneous and sedimentary rocks are changed into metamorphic rocks.

Detailed explanation-2: -Metals from rocks The rock or mineral that holds the metal is called an ore. An ore is heated with chemicals until it melts and the pure metal separates out as a liquid. The liquid then cools and hardens. A few metals, such as gold, silver, and copper can be found in pure form as metal elements.

Detailed explanation-3: -Gold and silver are commonly found in areas of igneous and metamorphic activity and are generally associated with silicic intrusives and Precambrian metamorphic rocks.

Detailed explanation-4: -Igneous rocks contain as little as 0.2 and as much as 73 ppb (parts per billion) gold. The average, calculated on the basis of 50 percent granite and 50 percent basalt, is 3.0 ppb.