The Philadelphia Museum of Art owns this exquisitely carved conch shell that is about 7 inches tall. It dates back to about the Eleventh Century A.D. and was probably made in or near Bangladesh. It shows the Hindu god Vishnu, who is often depicted using a conch as a war trumpet. The museum describes the scene:
Within the rondel on this shell Vishnu is represented in his martial role as protector of the universe. He flies through the sky on his mount, the bird-man Garuda, holding his weapons—the shell-trumpet, the mace, and the discus. Pierced conch shells are blown as trumpets to beckon the god during worship. This one, however, lacks a mouth opening on its spiral end and was probably used to hold and pour sacred water during religious ceremonies.
-via TYWKIWDBI