The rosary provides a physical method of keeping track of the number of Hail Marys said. The fingers are moved along the beads as the prayers are recited. By not having to keep track of the count mentally, the mind is more able to meditate on the mysteries. A five decade rosary contains five groups of ten beads (a decade), with additional large beads before each decade. The Hail Mary is said on the ten beads within a decade, while the Our Father is said on the large bead before each decade. A new mystery is meditated upon at each of the large beads. Some rosaries, particularly those used by religious orders, contain 15 decades, corresponding to the traditional 15 mysteries of the rosary. Both five and 15 decade rosaries are attached to a shorter strand, which starts with a crucifix followed by one large, three small, and one large beads before connecting to the rest of the rosary.
The praying of the rosary is started on the short strand, reciting the Apostle's Creed at the crucifix, an Our Father at the first large bead, three Hail Marys on the next three beads (for faith, hope and charity), then a Glory be to the Father on the next large bead. The praying of the decades then follows. Although counting the prayers on a string of beads is customary, the prayers of the rosary do not actually require a set of beads, but can be said using any type of counting device, by counting on one's fingers, or by counting by oneself without any device at all.
The beads can be made from a wide variety of materials including wood, bone, glass, crushed flowers, semi-precious stones such as agate, jet, amber, or jasper, or precious materials including coral, crystal, silver, and gold. Rosaries are sometimes made from the seeds of the "rosary pea" or "bead tree". Today, the vast majority of rosary beads are made of glass, plastic, or wood. Early rosaries were strung on strong thread, often silk, but modern ones are more often made as a series of chain-linked beads.
It is especially common for beads to be made of material with some special significance, such as jet from the shrine of St. James at Santiago de Compostela, or olive seeds from the Garden of Gethsemane. Beads are sometimes made to enclose sacred relics, or drops of holy water. A set of blessed rosary beads is a sacramental.
In addition to a string of beads the rosary comes in other forms for ease of use. A ring rosary is a finger ring with eleven knobs on it, ten round ones and one crucifix. A rosary bracelet is one with ten beads and often a cross or medal as well. The most modern form is the rosary card. A rosary card is either one with a "handle" that moves like a slide rule to count the decade, or it has a whole rosary with bumps similar to Braille.