Mani stone
Mani stones are stone plates, rocks, or pebbles inscribed with the six-syllabled mantra of Avalokiteshvara as a form of prayer in Tibetan Buddhism. The term mani stone may also be used to refer to stones on which any mantra or devotional designs are inscribed or painted. Mani stones are intentionally placed along the roadsides and rivers or grouped together to form mounds, cairns, or sometimes long walls, as an offering to spirits of place or genius loci. Creating and carving mani stones as devotional or intentional process art is a traditional sadhana of piety to yidam. Mani stones are a form of devotional cintamani.
The preferred technique is sunk relief, where an area around each letter is carved out, leaving the letters at the original surface level, now higher than the background. The stones are often painted in symbolic colours for each syllable, which may be renewed when they are lost by weathering.
Mani walls
Along the paths of regions under the influence of Tibetan Buddhism, mani stones are often placed in long stacks along trails, forming mani walls. Buddhist custom dictates that these walls should be passed or circumvented from the left side, the clockwise direction in which the earth and the universe revolve, according to Buddhist doctrine.They are sometimes close to a temple or chorten, sometimes completely isolated and range from a few metres to a kilometre long and one to two metres high. They are built of rubble and sand and faced with mani stones engraved in the elegant Tibetan script.