What is the origin of Rudraksha ?

Devala Rees
Rudraksha is a species of tree. Rudraksha trees bear fruits whose pyrenes (“stones”) are considered sacred by Dharmik peoples (Hindus, Buddhists, some Sikhs, etc.).
Rudraksha literally means “Rudra’s eyes”, but contrary to the obvious interpretation this does not mean that the Rudraksha beads themselves are meant to represent Rudra’s eyes. Rather, the intended sense is “from Rudra’s eyes”. The Hindu sacred story is that whenever the God Rudra sheds a tear, if His tear falls to earth, it sprouts into a Rudraksha tree. This is said to be the origin of Rudraksha. Mainly He sheds tears of love for the living beings of the Earth, in compassion for our suffering. There are various specific occasions in Hindu records of ancient times when Rudra is said to have wept – for example after slaying the demons of Tripura, for he was deeply sad that these beings whom he loved had turned to such evil that he had to kill them to protect the world.
Hindus wear garlands of Rudraksha beads as a sacred symbol around our necks because of its origin from Rudra. It possesses Divine properties. It grants spiritual protection, aids in prayer and meditation, and has a sanctifying effect on the mind and spirit. Its usage is prescribed in our scriptures. (Quora)