Shaped brown lava stone, hand wrapped for a trendy raw stone necklace (rough natural jewelry is hot right now!) Crystals formed in the air bubbles as the lava cooled - they also sparkle a bit in person, even though they are tiny.
The lava bead is about 4 cm (over 1 1/2 inches) long, not including the sterling silver bail. I have strung it on a 45 cm (18 inch) silver plated chain with a self-closing clasp.