Nacre

Definition

Nacre, also known as mother-of-pearl, is a composite material produced by some mollusks as an inner shell layer. It is composed of aragonite or calcite platelets and organic matrix proteins that give it its iridescent appearance.

5 Must Know Facts For Your Next Test

1. Nacre is primarily found in the inner shells of mollusks like oysters and abalones.
2. It is made up of microscopic aragonite (a form of calcium carbonate) platelets arranged in a brick-and-mortar structure.
3. The iridescence seen in nacre occurs due to the interference of light waves reflecting off the thin layers within the material.
4. Nacre is biologically significant for mollusks as it acts as a defense mechanism by smoothing over irritants or parasites that enter their shells.
5. Artificial synthesis of nacre has been studied for its potential applications in materials science and engineering.

Review Questions

• What types of organisms produce nacre?
• Explain the structural composition of nacre.
• How does nacre contribute to a mollusk's defense mechanisms?

Related terms

Mollusk: Invertebrate animals with soft bodies, often protected by a hard shell, including species like snails, clams, and squids.

Aragonite: A crystal form of calcium carbonate that is one component of nacre.

Pearl: A hard, lustrous spherical mass formed within the soft tissue of a shelled mollusk, mainly composed of nacre.