Rudraksha, also rudraksh, Sanskrit: rudrākṣa ("Rudra's eyes"), is a seed is traditionally used for prayer beads in Hinduism . The seed is produced by several species of large evergreen broad-leaved tree in the genus Elaeocarpus with ganitrus being the principal species used in the making of organic jewellery or mala. Rudraksha, being organic, is preferentially worn without contact with metal; thus on a cord or thong rather than a chain.The word rudraksha is derived from two words - rudra (रुद्र) and aksha (अक्ष).Rudra and aksha means the one who is capable of looking at and doing everything (for example, the third eye). Aksha also means axis. Since the eye can rotate on one axis, it too is known as aksha. Also Rudra means the one who weeps. A (अ) means to receive and ksha (क्ष) means to give. Hence, aksha (अक्ष) denotes the ability to receive or give. Rudraksha is the one that has the ability to wipe our tears and provide happiness.
The benefits have not been proven by science but rudraksha is believed to provide good support for those who are constantly on the move and who eat and sleep in a variety of places. This is because it is claimed to create a cocoon of the wearer's own energy. It is said that if the situation around one is not conducive to one's kind of energy, one will experience difficulty settling down. This was noted as being especially difficult for sadhus and sanyasis as they were constantly moving, and were traditionally never supposed to rest their heads in the same places twice. Likewise, the rudraksha may be helpful for travellers and professionals who eat and sleep in a variety of places.
Sadhus or sanyasis of almost all panths living in the forest would have to resort to naturally available water sources. A common belief was that, if the rudraksha is held above the water, it would go clockwise if the water was good and drinkable. If it was unfit for consumption, it would go counter-clockwise. This test was also believed to be valid for other edibles. When worn on a mālā, it was also said to ward off and act as a shield against "negative energies" for refrence i am showing picture osf my NAD-JANEU, this is age old practice to wear janeu like this amoungst The NTHA YOGIS , has a lot of deep meaning and significance in Nath yogis, it is used to do ADESH to SATGRU, and to Adesh at SAMADHI and dhuna ... more over it has been related to the KUNDALINI , the mantras are associated with the ADESH and given by the GURU during the intiation of YOGI. its important identity of Nath yogis and with constant and persistent yogic sadhna (mantra, asnas ,sidhis etc) the nath yogi achieves the goal of being called Nath. some remain grihisth (family) and some tyagi (leave home) .... the article is aimed only for information purpose and the deeper meaning of Adesh and nad janeu is complex to understand. can only be understood with penance and grace of true GURU (satguru)