Larvikite Norwegian black moonstone pendant

Carved larvikite or Norwegian black moonstone pendant. pretty blue flash. Sterling silver setting but no markings. purchased from a gem and mineral show. Larvikite is a feldspar-rich igneous rock, called a monzonite and is named for the town in Norway where it was found. One characteristic of this stone is its blue sheen or labradorescence, caused by the presence of interlocking feldspar crystals within the structure of the stone.