Rulestone (medieval)

The rulestone (rule-stone, king-stone, etc.) is a type of mineral (nonfiction) attested in several 13th–14th century written sources in Iceland, one of which describes its use to locate a king under adverse conditions.

Fiction cross-reference

• Crimes against geological constants
• Gnomon algorithm
• Gnomon Chronicles

Nonfiction cross-reference

• King (nonfiction)
• Mineral (nonfiction)
• Sunstone (medieval) (nonfiction)