The crystal habit of a mineral describes its visible external
shape. It can apply to an individual crystal or an assembly of crystals. In
mineralogy, shape and size give rise to descriptive terms applied to the
typical appearance, or habit of crystals. Each crystal can be described by how
well it is formed, ranging from euhedral, to subhedral, and anhedral. The many
terms used by mineralogists to describe crystal habits are useful in
communicating what specimens of a particular mineral often look like.
Recognizing numerous habits helps a mineralogist to identify a large number of
minerals. Some habits are distinctive of certain minerals, although most
minerals exhibit many differing habits. Crystal habit may mislead the
inexperienced as a mineral's internal crystal system can be hidden or
disguised.