Sphatik (rock crystal) is the purest and the most auspicious gem in the world.It believed that during "Ramayan Kaal": Lord Ram and Laxman sat on the sphatik rock. Any idol which is made of Sphatik does not need "Pran pratishtha" before worshipping. Worshipping a Sphatik shivling is considered to have same effect as worshipping the "Jyotirling"
Sphatik shivling is considered to be auspicious and praying and bowing down to sphatik
shivling is considered to be bowing to Lord shiva directly.
Nandi is the name for the bull which serves as the mount (Vahan)of the god Shiva and as the gatekeeper of Shiva and Parvati.
During the churning of the ocean when poison (halahala) came out everybody ran away except Lord Siva, followed by Nandi, came forward to help as He was the only one who could counteract this deadly poison. Shiva took the poison into his hand and drank it, the descent of the poison was in turn stopped at His throat, by His divine consort.