Mollusc products

thumb|Georgian seed pearl gold ring

right|thumb|Seashells washed up on the beach in Valencia, Spain; nearly all are single valves of [[bivalve mollusks, mostly of Mactra corallina]] right|thumb|Hand-picked molluscan seashells (bivalves and [[gastropods) from the beach at Clacton on Sea in England]] thumb|A group of seashells, mostly bivalves in the family Pholadidae thumb|226x226px|Mixed shells on a beach in Venezuela thumb|Hermit crabs inhabiting marine gastropod shells that lived in the [[Persian Gulf]] thumb|A group of beach-worn sea snail shells that vary in size, form and pattern combination.

thumb|upright=1.2|The iridescent nacre inside a nautilus shell thumb|upright=1.2|Nacreous shell worked into a decorative object

chemical compound

Clam is a common name for several species of bivalve mollusc. The word is often applied only to those that are deemed edible and live as infauna, spending most of their lives halfway buried in the sand of the sea floor or riverbeds. Clams have two shells of equal size connected by two adductor muscles and have a powerful burrowing foot. They live in both freshwater and marine environments; in salt water they prefer to burrow down into the mud and the turbidity of the water required varies with species and location; the greatest diversity of these is in North America.

thumb|A mussel (genus Mytilus (bivalve)|Mytilus), attached to a rock by its byssus thumb|Illustration of the byssus of Dreissena polymorpha, the freshwater zebra mussel A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilidae), and Dreissenidae.

thumb|Cuttlebone of Sepia officinalis (left to right: ventral, dorsal, and lateral views). The cuttlebone is about 15cm in length. thumb| thumb|Tortoise with cuttlebone thumb|Fossil cuttlebone of the Pliocene species [[Sepia rugulosa]] thumb|Fossilised cuttlebone-like gladius (cephalopod)|gladius of [[Trachyteuthis]]

exoskeleton of an animal in the phylum Mollusca

hard structure which closes the aperture of a gastropod when the animal retreats into the shell

dark pigment release

thumb|right|300px|Tzitzit produced from a blue dye derived from [[Hexaplex trunculus and tied according to the opinion of the Sefer ha-Chinuch, resting atop volumes of the Shulchan Aruch.]] thumb|upright|The flag of Israel, which emulates the tekhelet color for the [[Star of David and the two tallit-like stripes.]] thumb|upright|A contemporary tekhelet thread tied according to the method of the 18th-century rabbi Vilna Gaon. thumb|A Jew wearing blue tzitzit, 15th-century

large pearl

Ammolite is an organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is commonly unearthed by natural erosion or through the process of various mining practices, within the perimeter of an ancient sea bed called the Western Interior Seaway. It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral contained in nacre, with a microstructure inherited from the shell. It is one of few biogenic gemstones; others include amber and pearl.

mucus produced by gastropods

300px|thumb|right|Japanese horagai, a conch shell used for religious purposes or as a signal instrument|signal for [[samurai]] Horagai () (or jinkai ) are large conch shells, usually from Charonia tritonis, that have been used as trumpets in Japan for many centuries. The instrument, which has served a number of purposes throughout Japanese history, has been given a number of Japanese names depending on its function. Special schools still teach students to play the traditional music associated with the conch.

world's largest natural pearl