What is a conch made of?

Conch, also known as sea snail, is a marine gastropod mollusk. The shell of the conch is made up of calcium carbonate, which the mollusk secretes as it grows. The shell is composed of three layers, with the outer layer being the most colorful. The inner layer, which is nacreous, is highly iridescent. The conch shell is often used as a decorative object, and it can be turned into jewelry or musical instruments.