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The Pure Minerals
Mineralogists identify the following minerals as native elements: copper, gold, iron, iron-nickel, lead, mercury, nickel, platinum, silver, antimony, arsenic, bismuth, stibarsen, tellurium, diamond, graphite and sulfur. No definitive list exists, however, because the expansive nature of science allows for the discovery of new elements and minerals. Additionally, the chemical composition of several of the native elements includes multiple elements from the Periodic Table, making them not "pure" in the strictest sense. These elements are still classified in the native element/pure mineral group, though.
Categorization
Mineralogists divide pure minerals into subgroups using several methods. The most often used means of subdivision simply classifies these minerals according to metallic elements, semi-metallic elements and non-metallic elements.
The metallic minerals include copper, gold, iron, iron-nickel, lead, mercury, nickel, platinum and silver.
The semi-metallic minerals include antimony, arsenic, bismuth, stibarsen and tellurium.
The non-metallic elements include diamond, graphite and sulfur.
The Dana Classification System further divides the minerals into a greater number of groups, which are identified by the elements within them rather than overall group names.
Formation
Minerals form as both massive minerals and mineral crystals. Mineralogists identify crystals as mineral solids with a definite shape and noticeably flat sides. Crystals form when the liquid states of pure minerals cool and harden. Massive minerals form when the liquid form does not have sufficient space to cool, creating a large and unevenly formed solid.
Properties
Each mineral possesses its own distinct properties that vary according to the elements that make up the mineral. With the exception of iron-nickel and stibarsen (a mixture of arsenic and antimony), the minerals in the native elements group form purely with a single element. The pure minerals&' names reflect the respective elements that form the minerals, and the pure minerals&' individual properties reflect those of their respective elements as well. Additionally, every mineral forms its own distinct crystals, which scientists study by shape, luster, transparency, color, fracture, tenacity, density and hardness.
Dana Classification System
The Dana Classification System divides the pure minerals into further subgroups. This system leaves the subgroups unnamed, identifying the groups by only the elements within them. Additionally, this system includes more minerals than those previously mentioned, such as kamacite, taenite, tetrataenite, awaruite, arsenolamprite, rosickyite and chaoite. While mineralogists refer to this system on occasion, the previously mentioned classification system remains the most common.