Devil’s stone

The volume of the devil’s stone has been calculated at 36 m³. Its weight is estimated at 100 tonnes. The rock consists primarily of a course-grained granite, termed pematite, which is characterised by the easily identifiable 1-3 cm large potassium feldspar crystals (microcline). The pegmatite is accompanied by a fine-grained gneiss, recognisable by its brownish colour and often smooth surfaces (cleavage surfaces). The devil’s rock comes from Scandinavia (Finland, Sweden), although its precise origin cannot be determined. It is approximately 1.8-2.0 billion years old. The name “devil’s stone” has its roots in a legend. Long ago, the devil in human form is said to have attempted to marry the beautiful daughter of a miller. The miller’s wife, however, recognised the devil and thwarted its efforts. In anger, the devil hurled a large stone at the mill, narrowly missing its target.