Black Obsidian Arrowhead Necklace Small gold-plated black obsidian arrowhead necklace. Arrowhead size is approximately 1 inch. Gold plated chain. 16 inches. Lobster Clasp. Obsidian is thought to be a strongly protective stone. It helps shield against negativity and unloving thoughts and helps bring mental clarity. It draws out stress and tension. These are natural stones and will vary slightly in shape and size. ✨3 for $20 sale: Add 3 items to a bundle and make an offer for $20.