There have been over 4000 minerals identified by mineralogists, but only about the hundred or so are easily collectable. Some collectors want to obtain a piece of every known species, but this is impossible because some are so rare. Properties of minerals You can tell the differences between minerals by looking for certain properties. Because each mineral is unique both chemically and structurally, each has its own set of physical, optical, and structural properties which aid in its identification. Chemistry refers to the basic building blocks that the mineral is made of.
Optical properties are the way a mineral looks and what light does when it shines on it.
Physical properties such as hardness and streak can be tested easily. Most geologists only do the most basic physical property tests for an identification, so we will briefly discuss some physical properties. Physical properties Let's consider the physical properties that are easy to test. These are color, luster and diaphany. You can do all of these light tests using only your eye.