Mani Stones

Mani stones are stone plates or rocks that are carved with the Tibetan Buddhism mantra such as six-word mantra "Om Mani Padme Hum" and text. 

Mani stone is the one of the most popular forms of prayer and ritual in Tibetan culture.  The most mantra you see on Mani stones are  "Om Mani Padme Hum" , so what mantra means; 

Buddhist philosophical study is limitless like sky but all those can be conclude this six words. The Mantra has huge meaning and practices. It is Buddhisatva pray for all six type of sentient beings. The six word mantra prays happiness and enlightment to all six  type of sentient beings. 

• The six type of sentient beings include the three lower types, hells, hungry ghost and animals and the three higher types, namely: humans, demigods, and gods. 

when it comes to one's own practice, it means;

The Meaning of Om Mani Padme Hum

The first word, Om, symbolizes the practitioner’s impure body, speech, and mind; it also symbolizes the pure exalted body, speech, and mind of a Buddha. Mani, meaning jewel, symbolizes the factors of method: altruistic intention to practice compassion and love.

Padme, meaning lotus, symbolizes wisdom. Purity must be achieved by an indivisible unity of method and wisdom, symbolized by the final syllable hum, which indicates indivisibility.

Thus the six syllables, om mani padme hum, mean that in dependence on the practice of a path which is an indivisible union of method and wisdom, you can transform your impure body, speech, and mind into the pure exalted body, speech, and mind of a Buddha.