Different Types of Crystals

Crystals are solids composed of a specific molecular makeup. They are all based on a single molecular strand, which is a combination of various elements. This strand is repeated multiple times and all are bonded together, extending in all directions from the starting molecule. There are a number of different types of crystals, each type containing a number of specific crystals. The following are some of the basic classifications of naturally forming crystals.

Isometric

Isometric crystals are formed with the same lengths along all axes. They can have four faces (cubes), eight or ten, all of equal sizes.

Hexagonal

These crystals have six flat faces of the same size. When cut in half, the cross-section of these crystals will form a hexagon.

Covalent Crystals

These crystals have covalent bonds between all the molecules that make them up, meaning that electrons are shared between bonded molecules. These can be looked at as one giant molecule, and they typically have very high melting points.

Ionic Crystals

The molecules in these types of crystals are held together by electrostatic forces. They are very hard; one example of this type of crystal is common table salt.

Molecular Crystals

These types of crystals are very soft, as opposed to other types of crystals. This is because their bonds are noncovalent and weak, such those formed with hydrogen.