Different layers of the shell will have different proportions of calcite, aragonite, and the organic material: the hypostracum, for example, has a much higher proportion of aragonite than the subnacreous layer, which has multiple sheets of calcite separated by conchiolin
proteins; the prismatic layer has crystals of both calcite and aragonite; the periostracum is composed almost entirely of organic material (Galtsoff 1964).
calcium phosphate), and the phosphorylated protein conchiolin
is abundant in their soft tissues, playing a key role in the aggregation of minerals and organic compounds to produce shells (Cariolou & Morse, 1988).
The middle layer is the prismatic layer, which contains curved, wedge-shaped prisms of calcite crystals within a conchiolin
matrix (Galt-soft 1954, 1964; Mount et al.
When the oyster senses an irritant, it begins to coat it with layers of a crystalline mineral known as aragonite, cemented with a material called conchiolin
The core of those structures is made of a protein called conchiolin
, a common component of many mollusk shells.
It coats an irritant - such as a grain of sand - with layers of aragonite and conchiolin
, and the composite material is called nacre.
If the mollusc is unable to get rid of the irritant, as part of its defence mechanism it produces conchiolin
(an organic glue) and nacre (calcium carbonate crystallised in the form of aragonite).
This iridescence is due to interference between the alternating layers of conchiolin
The marine bivalve family Corbulidae has independently evolved conchiolin
layers and the presence of the layers is characteristic (i.
The condition was characterized by the presence of rigid blisters of shell and conchiolin
materials at the myostracal surface of adductor muscle attachment to the valves, which contained brownish, viscous liquid.
BRD symptoms in adult animals resulting from conchiolin
deposits in inner parts of carpet shell were observed in all zones surveyed.
covered with nacre) that projected into the mantle cavity to isolate the shell-boring polychaetes.