I am not sure what the material is that these beads are made of, It feels like stone. The tooth test feels like stone. They are black in color with the hole drilled through the length of the bead. They measure 1/2" Long x 1/4" thick and wide. Each bead is heavy for there size as well. See photo with ruler. The closeup photo looks speckled in a way. The beads look just black to the eye. The person who gave them to me said they were from the 80s.