In ice, the molecules are scrunched together with no room at all. The type of substance made up of certain molecules like sugar or salt also effects the behavior of the molecules in different circumstances. All matter comes in one of three forms-solid, liquid, gas. Crystals can be formed by all three of these. When water freezes, it is a solid, water is already a liquid, and when water evaporates, it becomes a gas.
All crystals have a definite shape.
For crystals to form, they need time and freedom to grow. Crystal formations form from solutions, the combination of one state of matter into another. Some examples are-liquid into liquid, and gas into gas. All crystal growth patterns are ordered. No one really knows how crystals can join together and make the amazing formations like rubies and diamonds.