Lost mines are a popular form of lost treasure legend. The mine involved is usually of a high-value commodity such as gold, silver or diamonds. Often there is a map (sometimes called a "waybill") purportedly showing the location of the mine. Common reasons given for the mines being lost include: Some lost mine legends have a historical basis; some have none. But the lure of lost mine legends is attested by the many books on the subject, and the popularity of publications such as Lost Treasure magazine.