Black Onyx Rope Design Bolo Tie. Cut from natural black onyx rough, most of this material is dyed to assure uniform blackness. Extremely well-cut and polished. Black onyx has traditionally been used to banish grief and enhance self-control. Allow 3-5 days for production, each unit is made to order. Includes Matching Gold or Silver tips and rope. Size 1 3/4 x 2 1/4 inches.