Snowflake

Though commonly known as a snowflake, the items in these photos are actually snow crystals  (a snowflake is made up of multiple snow crystals). Snowflakes might all look the same, but snow crystals occur in many different shapes, and experts classify them in as many as 41 types. What determines the basic shape of snow crystals is the temperature at which they form and the humidity of the air. For example, long needle-like crystals form at 23 °F and very flat plate-like crystals form at 5 °F.