Malas are basically a tool for counting chants or prayers. The gemstones used in the malas may also contain healing properties.
Buddhist prayer beads, traditionally called malas, first developed as a religious tool on the Indian continent. "The use of beads in prayer appears to have originated with Hindu religious practices in India, possibly around the 8th century," writes the Museum of Anthropology at the University of Missouri. "B.C.E. Buddhism, which developed from a sect of Hindu culture, retained the use of prayer beads as it became established in China, Korea, Japan, and Tibet."
Most Buddhists normally utilize mala consisting of 108 beads, but the number may vary in different sects of Buddhism. Just like the Hindu variety, Buddhist mala consist of a strand of 108 beads (not including marker beads, decorative beads or guru bead), each a symbol of impurities and flaws that an individual must overcome.
108 beads is said to represent the following formula:
The Buddha himself is believed to have instructed followers to utilize mala. "There is a Sutra (Buddhist Text aka. "thread of knowledge") in which a King prays to the Buddha for a simple practice to help ease his suffering from various difficulties and the Buddha responded by telling him to string 108 soapnut seeds and recite the three part refuge prayer upon them."
The word mala, also referred to as jap mala, is derived from the Indian Sanskrit phrase for garland. The English word rosary, the western term for prayer beads, owes it's etymology to Roman miscommunication. "When Roman explorers came into India and encountered the mala, they heard jap mala, and jap for the Romans meant 'rose,'' according to ReligionFacts.com. The word "rosary" eventually evolved from that translation as Romans carried the prayer bead concept back to the western world. (Courtesy of EHow)
Want to learn more? Learn how to use a mala properly.