It was originally a weapon of ancient India. It has a strong texture and can break through various substances. Vajra is also a Sanskrit word meaning both thunderbolt and diamond. It can be used as a weapon which is used as a ritual object to symbolize both the power of indestructible diamond and irresistible force of thunderbolt
It is the symbol of the esoteric doctrine of the Buddha and represents Tantrism. And also represents a firmness of spirit and spiritual power, being one of the important sacred tools and ritual implement in Vajrayana Buddhism, Hinduism and Tantra where it symbolizes the male principle of creation and represents both method and “Upaya” (means “skillful” ) in religious practice. When made to be worn as a pendant, it reminds the wearer, and the viewer, of the supreme indestructibility of knowledge. In the Tantric traditions of Buddhism, it also symbolizes for the nature of reality, or sunyata.
In Buddhist tantra, it symbolizes the invincible and indestructible wisdom and true Buddha-like nature. It can cut off all kinds of troubles and destroy demons of all kinds of obstacles. It is the holder of esoteric sects or the magical tool of yogi. And all deities of the Mandala hold this special buddhism iiImplement. Mantra practitioner often carry it, because it symbolize the Vajra-Wisdom of Sakyamuni, which is used to break the inner demon and the outer demon barrier of foolish delusion.