For your consideration are these black Sardonyx (also known as Sulemani Again or Banded Agate) crystal bead power bracelets, sold by the piece.
The Sardonyx crystal beads are 8mm in diameter. The crystal bracelet itself measure approximately 7 inches long, unstretched, and one size fits most.
Sardonyx is a crystal of strength. Brings stability and happiness to relationships. Aids in happiness, courage and protection.
Chakra: Root