For sale: Unicorn (Hippopotamus) horn prayer beads. Distinctive color and clean material. 33 beads. Weight: 44.1 grams. Bead size: 12 mm. It has been evaluated as rhinoceros horn by Abdul Rahman Al-Mu'min's shop (Abu Hisham), a prayer bead expert known for his expertise in the Al-Thumairi market in Riyadh.