Physical Properties

Physical properties of minerals are often the only guidelines for field identification of specimens that may occur combined with other minerals or in very small amounts in a particular sample.

1. Minerals grow into consistent crystal shapes, which are controlled by the chemical composition of the minerals. There are six crystal systems that include all minerals. Some mineral compounds can form more than one mineral with entirely different crystal structures.

Some examples of the crystal form are:

· isometric,

· elongated,

· flattened.

2. How a mineral resists scratching is the measure of its hardness. A mineral will resist scratching or demonstrate its hardness relative to the substance used to scratch it or the substance that the mineral can scratch. German mineralogist Friedrich Mohs developed a hardness scale involving ten minerals from the softest to the hardest during the 19th century. His scale, known as Mohs hardness is the standard by which mineral hardness is determined. Only fresh mineral surfaces should be tested for hardness.