The 90-degree grid pattern of the galena crystal structure

As the crystal grows, locations like these attract sulfur atoms, while lead will tend to bond to these places. Eventually, they will complete the grid of bonded atoms. This means the 90 degree grid pattern of galena’s crystalline structure is reflected in the visible shape of the crystal. Quartz, meanwhile, has a hexagonal crystalline structure. This means that on one plane its atoms are arranged in hexagons.