Lake Superior Stone Necklace This Basalt Fish Necklace is a rarity indeed! Long, skinny pieces of basalt are hard to find. When I get enough to use, this is what I like to make! The fish itself is 3 long and the black rubber cord is 18. With sterling silver jump rings, crimp ends and clasp. Basalt covers 90% of the Lake Superior Basin, and is known for providing strength and enhancing creativity.