The mineral halite has cube-shaped crystals because:

• A. The arrangement of atoms in the crystal lattice
• B. Because it forms in open spaces
• C. Because it is a metal
• D. Because it has a strong fracture

Answer: (A)

Cube-shaped crystals come from a highly symmetric arrangement of atoms in the crystal lattice. Halite crystallizes in the cubic (isometric) system, where the ions stack in a three‑dimensional grid with equal lengths along all three axes and right angles between them. That uniform symmetry makes the crystal faces grow in the same directions, often forming six square faces that enclose a cube. In halite, sodium and chloride ions arrange in a rock‑salt lattice, with each ion coordinated in a way that reinforces this cubic symmetry. The cube shape isn’t about open space, being a metal, or fracture behavior—it's the lattice’s three‑dimensional symmetry showing up as the external cube.