In three dimensions, these hexagons are made up of one silicon atom and four oxygen atoms

In three dimensions, these hexagons are composed of many interlocking pyramids made up of one silicon atom and four oxygen atoms.So the signature shape of a quartz crystal is a six-sided column with pointed tips. Depending on environmental conditions,most crystals have the potential to form multiple geometric shapes. For example, diamonds, which form deep in the Earth’s mantle, have a cubic crystalline structure and can grow into either cubes or octahedrons.