I have heard many people saying Nagamani is obtained from a naga type of snake and my questions are as follows:
1) What are the rules for a snake to give nagamani?
2) What happens when the snake spits the nagamani out of its hood?
3) Is there a original nagamani in the world ?
As per this page:
Most People believe Naga Mani Generally forms in the hood of a cobra or king cobra. Actually it is not formed in the poison gland., but the higher cobra spirit of Naga Loka, chooses one highly special, spiritual and magical stone for itself. One is very lucky to get such a unusual gem of Naga Loka. Naga Mutya or Naga Manikya stone is blessing of Naga gods. It blesses one with the magical fortune and good luck. The snake god which hold this pearl belong to Vasuki race according to Bruhat Samhita of the great Varaha Mihira. This mani creates magic in your life. This rare magical item is only the wealth of Naga Loka. Naga Land, India, is the only place on earth which has relation with Naga Loka.
A state of India known as Nagaland is famous for this Mani. Sometimes we come across normal stones in forest which is a Naga Mani. An expert shaman only acquire it by spiritual vision. No body can get it by killing a cobra.
Maha Naga Mani: Anyone possessing such a Naga Mani or cobra stone attains piety, rare good fortune, and eventually becomes illustrious as a leader of men, complete with a great collection of all precious gems. King Vikramaditya, Raja Bhoj, King Solomon and many other Indian kings, possessed such a precious treasure.
Question 4-In which Hindu Scripture do we find more details regarding these Nagamanis or Cobra Pearl?