What Are Some Characteristics of All Minerals?

Some important characteristics of minerals are color, hardness, streak, cleavage, fracture and luster. These characteristics do not require any complicated equipment to determine and are useful in identifying specific minerals.

Color is the easiest mineral characteristic to observe and provides the first clues to identification. Holding translucent minerals against a white background is a good way to determine accurate color. Hardness is a mineral's resistance to damage, and testing this is as simple as scratching a mineral with a material of known hardness. The Mohs scale is a common measure of mineral hardness that ranges from 1, the softest minerals, to 10, the hardest. According to the Mohs scale, talc has a hardness of 1 and diamond a hardness of 10.

Rubbing a mineral across a porcelain plate yields a line of powder; this is the mineral's streak. Streak is important because it is much more consistent than color. For example, five samples of the same mineral might all differ slightly in color but all have the same streak. Streak is also important because two different minerals with nearly identical coloration might have different streaks.

Luster refers to the way a mineral reflects light. A mineral might appear dull, metallic, silky, oily or brilliant. Cleavage and fracture both deal with how a mineral breaks. Cleavage refers to breakage along lines of weakness while fracture is breakage elsewhere in the mineral. Minerals fractures are conchoidal, irregular or hackly. Respectively, these are smooth, rough and jagged fractures.