The Nirvana, or Parinirvana Sutra is a Mahayana Buddhist text that teaches about the death of the Buddha. It works to solve the epistemological problem of glorifying and supernaturalizing the death of the Enlightened One by drawing in multitudes of gods and spirits and defining the character of a enlightened being’s death. Among the information presented in this sutra is the necessity for a monk to die fully conscious, and the conversion of a deceased monk’s body to special crystals, or sarina.
``It was the fifteenth day of the second month that the time of his entry into Nirvana was imminent. Using the Buddha's spiritual power, he issued a great voice that filled the minds of beings everywhere. Conforming to each species, this voice addressed all the sentient beings, saying, `Today the Tathagata, the Worthy, the Completely Enlightened One, feels compassion for sentient beings, ... for the sake of those who have taken refuge and those who are worldly householders, the greatly awakened World Honored One now wishes to enter Nirvana. If any sentient being has uncertainties, they can now submit the very last questions.'" - (Parinirvana sutra, introduction)