AbaloneAbalone (ˈæbəloʊni or ˌæbəˈloʊni; via Spanish abulón, from Rumsen aulón) is a common name for any of a group of small to very large marine gastropod molluscs in the family Haliotidae. Other common names are ear shells, sea ears, and, rarely, muttonfish or muttonshells in parts of Australia, ormer in the UK, perlemoen in South Africa, and pāua in New Zealand. Abalones are marine snails. Their taxonomy puts them in the family Haliotidae, which contains only one genus, Haliotis, which once contained six subgenera.
HaliotisHaliotis, common name abalone, is the only genus in the family Haliotidae. This genus once contained six subgenera. These subgenera have become alternate representations of Haliotis. The genus consists of small to very large, edible, herbivorous sea snails, marine gastropod molluscs. The number of species recognized worldwide ranges between 30 and 130, with over 230 species-level taxa described. The most comprehensive treatment of the family considers 56 species valid, with 18 additional subspecies.
AragoniteAragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The crystal lattice of aragonite differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms.
Mollusc shellThe mollusc (or mollusk) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and solenogastres.
Carbonate rockCarbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolostone), which is composed of mineral dolomite (CaMg(CO3)2). They are usually classified based on texture and grain size. Importantly, carbonate rocks can exist as metamorphic and igneous rocks, too. When recrystallized carbonate rocks are metamorphosed, marble is created.
NacreNacre (ˈneɪkər , ˈnækrə ), also known as mother of pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as flame structure as is found in conch pearls.
BelemnitidaBelemnitida (or belemnites) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard. The calcitic guard is the most common belemnite remain. Belemnites, in life, are thought to have had 10 hooked arms and a pair of fins on the guard.
Carbonate platformA carbonate platform is a sedimentary body which possesses topographic relief, and is composed of autochthonic calcareous deposits. Platform growth is mediated by sessile organisms whose skeletons build up the reef or by organisms (usually microbes) which induce carbonate precipitation through their metabolism. Therefore, carbonate platforms can not grow up everywhere: they are not present in places where limiting factors to the life of reef-building organisms exist.
Aragonite seaAn aragonite sea contains aragonite and high-magnesium calcite as the primary inorganic calcium carbonate precipitates. The chemical conditions of the seawater must be notably high in magnesium content relative to calcium (high Mg/Ca ratio) for an aragonite sea to form. This is in contrast to a calcite sea in which seawater low in magnesium content relative to calcium (low Mg/Ca ratio) favors the formation of low-magnesium calcite as the primary inorganic marine calcium carbonate precipitate.
Calcium carbonateCalcium carbonate is a chemical compound with the chemical formula . It is a common substance found in rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale.
