Physical Properties

Physical properties of minerals are very helpful for identification purposes. A mineral is solid and crystalline in structure. It is an inorganic, naturally occurring, homogeneous substance, with a definite chemical composition.

Minerals have the following physical properties:

• Hardness: Refers to the strength of mineral blocks. Diamond is the hardest known substance and all the other minerals are measured against it.

• Streak: Refers to the color of a mineral in powdered form.

• Luster: Refers to the way in which any mineral reflects light.

• Color: Represents the natural color of a mineral block.

Chemical Properties

Chemical properties account for many commercial uses of minerals. Chemical properties of minerals include:

• Chemical formula: Provides information about the chemical composition of minerals.

• Composition: Represents all the elements present in minerals.

• Empirical formula: Refers to the formula derived from the molecular formula of a mineral.

Optical Properties

Minerals exhibit the following optical properties:

• Pleochromism: Refers to the change in color as minerals are shifted from one place to another.

• Refractive Index: Refers to the ratio of the angle of incidence of light on the mineral to the angle of refraction. Based on the molecular axis, minerals are classified as biaxial or multi axial.

Among the...