hysical Properties of Minerals
Minerals have distinct physical properties that can be used to correctly identify the name of a mineral. The properties that are commonly used are hardness, streak, luster, cleavage or fracture, color, and a few more specific properties such as magnetism and odor.

Hardness is the resistance of a mineral to being scratched. This test is also the most useful in narrowing down the type of mineral to be identified. The Moh's Scale of hardness lists ten minerals in order of hardness from 1-10 with 1 being the softest and 10 being the hardest. Mineral hardness may be compared to other minerals or to the hardness of common materials such as a fingernail (2.5), copper penny (3.5), iron nail (4.5), glass (5.5), steel file (6.5), and a streak plate (7.0). See Moh's Scale of Hardness below.

Streak is the powder or residue left after a mineral has been scratched on a streak plate. Note: the color of the powder does not always resemble the color of the mineral. For example, Galena is a shiny sliver but will leave a dark gray streak.

Luster is the shine a minerals might posses. Usually if a mineral shines it will have a metallic luster. If not it is classified as a non-metallic mineral. For example, Galena has a shiny appearance like tin foil thus it is a metallic mineral.

Cleavage or fracture is how the mineral will break apart. If the mineral break apart in similar pieces it is said to have good cleavage. And if the mineral breaks like a piece of glass with uneven, jagged edges it would be classified as fracture. An example of a mineral with good cleavage would be Galena. If Galena breaks it breaks into cubes called “cubic cleavage”. There are other forms of cleavage, refer to your text to research them. An example of fracture would be Quartz. If Quartz were to split it would break in all different shapes and sizes. Due to this Quartz is said to have good fracture.

Color may be used but is not always a good identifier due to many minerals having the same color or the same minerals having multiple colors. This is true with quartz. Due to the amount of trace elements in a quartz sample the colors that can be found range from red to purple and even clear. So as one can see color would not be useful to identify a quartz sample.

Magnetism may be used to identify if a sample has iron (Fe) properties. The strongest attraction to a magnet will be found in the mineral magnetite.

Odor and taste may also be used, but these would most likely identify only two minerals they are: sulfur and halite.