Volcanic lightning is a rare phenomenon that occurs during volcanic eruptions. There are two types: lightning near the mouth of an erupting volcano, and lightning within the towering plume high above the volcano. The charge for the lightning is believed to come from either volcanic ash, magma and rock, or from rising water and ice particles coating ash. Volcanic lightning is difficult to study directly due to occurring within cloud cover during eruptions. Photos from eruptions in Iceland in 2010 and Japan in 2006 provide examples of the unique lightning.