This visualiser renders the unit cells of ten common crystal structures as interactive 3D projections. Drag to rotate the structure and scroll to zoom. The structures covered range from simple metallic lattices, such as simple cubic, body-centred cubic (BCC), and face-centred cubic (FCC), through to hexagonal close-packed (HCP), diamond cubic structures and ionic and compound lattices including rock salt (NaCl), caesium chloride (CsCl), zinc blende, fluorite, and perovskite. For each structure, the viewer displays the number of atoms per unit cell (accounting for sharing between cells), coordination number, packing efficiency, and example materials. Crystal structure is fundamental to materials science, solid-state chemistry, and condensed matter physics, governing mechanical, electrical, and optical properties of materials.