What describes natural crystal faces that take on a specific geometric shape?

The term that describes natural crystal faces taking on a specific geometric shape is crystal form. This concept refers to the external shape of a crystal, which arises from the internal arrangement of atoms. Each mineral has a distinct crystal form that reflects its chemical composition and the conditions under which it crystallized. These geometric shapes are characterized by the arrangement and orientation of the crystal faces.

While related terms exist, crystal structure refers more broadly to the three-dimensional arrangement of atoms within the crystal, which may not directly relate to the observable external shape. Similarly, crystalline lattice focuses on the orderly arrangement of points in three-dimensional space, representing the repeating units in the structure, rather than the external morphology. Crystal habit is another related term, often used to describe the typical external shape that a crystal takes as a result of its growth conditions, but is less precise when talking about the specific geometric shape. Thus, crystal form is the most precise and appropriate term for describing the geometric shapes of crystal faces.