Buccinella caerulea Perry, 1811 Turbinella pyrum, common names the chank shell, sacred chank or chank, also known as the divine conch or referred to simply as a conch, is a species of very large sea snail with a gill and an operculum, a marine gastropod mollusk in the family Turbinellidae.

The name "chank" for the shell of this species is derived from the Indian word shankha, the divine conch.

It is usually pure white under a heavy brown periostracum, but it can also be a pale apricot color.

In these religious contexts, the shell is sometimes modified by having the tip of the spire cut off, so it can be blown as a ceremonial trumpet.

In the Hindu religious context, the very rare left-handed (sinistral) shells of this species are known as Dakshinavarti Shankh in Sanskrit or Valampurich chanku in Tamil, as opposed to the more common right-handed forms, which are known as Vamavarti.