Minerals that are composed of atoms from a single element are referred to as native elements.
The minerals in the gold group all occur together in the periodic table of elements and have a common crystal structure. They all are soft, can be hammered out into thin sheets (malleable), drawn into wire (ductile), and cut into thin shavings with a knife (sectile). All are excellent conductors of heat and electricity, display metallic luster, have low melting points, and unusually high specific gravities.
The minerals in the platinum group include a number of rare minerals. These minerals are harder and have higher melting points than those in the gold group.
In the iron group, the element nickel is the same size as iron (has the same atomic radii) and can substitute for some of it. This is known as a solid-solution. Iron-nickel solid solutions are found in metrorites and compose a large part of the Earth’s core.
The minerals of the semimetals group are rather brittle and less effective conductors of heat and electricity in comparison with the metals. These properties are due to the type of bonding between the atoms. The structure is made up of sheets that are weakly bonded together, giving rise to cleavage.
