Artist's charcoal is a form of dry art medium. Compressed charcoal is produced from powdered charcoal binded with a gum or wax material. It is available in a range of hardness based on the ration of charcoal to binder. Willow and vine charcoals are made from grape vines and willow branches which have been burned to a certain degree of hardness. These charcoals erase more completely and are often powdery and very soft. Compressed charcoal is generally harder than willow and vine.