Lab 3: Minerals II - Native Elements

 

The native element minerals are those that are found in pure form, as with graphite, made of carbon only.

 

Graphite

 

Chemical formula: C

 

Structure: Each carbon atom is covalently bonded to three other surrounding carbon atoms. Flat sheets of carbon atoms are held together by weaker intermolecular forces, leading to the softness of this mineral. Graphite is a good conductor of electricity, because of a special way the carbon bonds form in part of the structure. Graphite is a polymorph of diamond.

 

Hammer behavior: Graphite is so soft that it can be used as a pencil lead, which is the reason for the name.

 

Color: gray to black, or steely black

 

Streak: dark gray

 

Luster: greasy feel

 

Diaphaneity: opaque

 

Hardness: 1

 

Occurrence: Graphite can be thought of as the highest grade of coal in some instances, where it represents original coal that was metamorphosed to a higher grade.

 

Use: Graphite is a good lubricant, and has also been used as a fire retardant and as part of nuclear reactors.