WHAT IS A MINERAL

 WHAT IS A MINERAL?
A ''mineral'' is any substance found in the earth's crust that does not come from a living thing.
Sometimes petroleum, coal, and limestone are called minerals, but since they were made from plants or animals which lived on the earth a long time ago, they are not really minerals.
Minerals are usually divided into two groups, metallic and nonmetallic. Examples of metallic minerals are hematite ( iron ), bornite ( copper ), and bauxite ( aluminum ). The non-metallic minerals include quartz, asbestos, and calcite. Minerals are usually found n forms called ''crystals.''
It is easy to confuse minerals and rocks, but there is a difference. A mineral has a definite composition. The chemical make-up of a mineral is almost always the same, no matter where it is. So a mineral foud in any part of the world will have the same luster, hardness, and other properties.
Rocks, however, are made up of mixtures of several minerals.For example, granite is a rock made up of minerals like quartz, feldspar, mica and others. But a piece of granite found in one place might have different amounts of these minerals from a piece of granite in another place.
Minerals are found in many places. They may be found in rocks or in sands and gravels. And they are formed in many different ways. Many minerals crystallized or hardened years ago from a very hot, melted mass of rock, called '' a magma.'' Diamond, mica, and feldspar are examples of minerals that formed from moten magma.
Certain minerals, chiefly because of their beauty and scarcity, are very valuable. These are called ''gems'' Some examples of valuable gem minerals are diamond, garnet, topaz, and zircon.
Some minerals, on the other hand, are found almost everywhere. The most common mineral is quartz. There are about 200 different kinds of quartz and it is found in almost every part of the earth.