Which property of minerals refers to the external shape they tend to form?

The external shape that minerals tend to form is known as crystal shape, which reflects the internal arrangement of atoms within the mineral. Crystals grow in specific geometric patterns that correspond to the mineral's atomic structure, leading to recognizable shapes such as cubes, prisms, and hexagons. This characteristic is significant in mineral identification, as different minerals will exhibit distinct crystal forms due to variations in their chemical composition and the conditions under which they crystallized.

Understanding crystal shape is crucial in geology since it not only aids in distinguishing one mineral from another but also provides insights into the conditions of formation, such as temperature and pressure during crystallization. In contrast, color, density, and streak pertain to other physical properties of minerals that do not specifically relate to their external geometric shapes.