Anything made by man, or produced through an organic means cannot be considered a mineral. A definite chemical composition means that each time any sample of a given mineral is broken down chemically, quartz for example, will always produce the same ratios of elements. In quartz , the ratio will always be two oxygen atoms for every silicon atom. This means that minerals can be expressed by a chemical formula, SiO2 for quartz. We now know what defines a mineral.
Geologists have several simple tools that can be used to help identify a mineral sample.
These tools use the physical properties of the mineral to give you clues to match the mineral by use of a mineral identification key. The physical properties include color, streak, luster, hardness, crystal form, cleavage, fracture, specific gravity, and other unique properties. We will take a look at each of these in turn. Color is the first thing a person will notice about a mineral. It is important to not overly rely on color as a diagnostic tool.