Final answer:
Crystal habit is determined by the mineral's growth rate in different directions, not by factors such as streak color or luster, which describe other properties.
Step-by-step explanation:
Crystal habit, such as needle-like, platy, or cubic, depends on the mineral's growth rate in different directions. This is because the way a crystal grows can be influenced by the environment in which it forms, including temperature, pressure, and the presence of other chemicals. While factors such as streak color and luster describe different properties of minerals, they do not directly affect the crystal habit. The regular and orderly arrangement of ions in a crystal lattice is chiefly responsible for the variation in crystal habits.
The streak of a mineral refers to the color of its powdered form and has more to do with the diagnostic aspects of metallic minerals. Luster describes how light interacts with the surface of a mineral and while it adds to the overall appearance, it is not a determining factor in the formation of crystal habits. Similarly, the color and brilliance of ionic crystals are influenced by the presence of transition metal ions, but this does not dictate the shape or habit of the crystal.