In a little more detail...

There are clefts called Mukhi on the surface of the beads. The number of Mukhi on the surface of a Rudraksha beads helps in determining its quality. According to the number of Mukhi the Rudraksha bead ranges from single face to a several faced bead. Asians have used Rudraksha beads traditionally. Asian Yogis and Monks found that merely wearing the Rudraksha beads gave them astonishingly tremendous amount of tranquility, concentration that helped them meditate for a long period of time with spectacular control over their mind.