Type of cleavage exhibited on minerals that crystallize in the hexagonal system and as rhombohedrons, in which small rhombohedrons cleave off of the existing rhombohedron. Example = Calcite.

The rock a mineral or minerals is found implanted in.

(HCl),(HNO3) Mixture of hydrochloric and nitric acids. It is an extremely destructive mixture and can dissolve gold and platinum, as well as many other minerals.

Composed mostly of clay.

The present term describing something displaying labradorescence.

Sedimentary rocks consisting of many thin layers.

General term describing the capability of a mineral with a habit of giving off light when put under certain conditions. Three examples of luminescence are fluorescence, triboluminescence, and thermolu [..]

Not containing any crystals (i.e. amorphous mineral or variety of mineral).

Igneous rock containing large, noticeable crystals, usually feldspars.

Having the attributes of a semi-metal.