Ivory

Structure

The chemical structure of the teeth and defenses of the Mammifère S is same whatever the species of origin. The ivory is composed of dentine and results from the progressive Calcification from the Pulpe. In the long term, the calcified envelope and the enamel are substituted by this ivory. The ivory is thus a mixture of organic matter and Hydroxyphosphate of Calcium.

Generally, the structure of the ivory can be compared with that of the Bois: the ivory taken on an elephant recently deceased contracts while drying (one speaks about green ivory ); it can just as easily inflate in a wet environment; once dry, there remains fragile along fibers. In addition, gradual calcification is directly visible on a section of defense, since, with the image of cerceaux concentric of the tree trunks (Dendrochronologie), it is possible to note the stages of the formation of the ivory on the concentric circles surrounding the core, and to deduce the age from it from the elephant.

The trade of certain teeth and defenses other than the elephant well is established and spread. Also, the term ivory can be correctly used to describe any tooth or defense of mammal of commercial interest which is sufficiently large to be carved.

Teeth and defenses

The teeth and defenses have the same origin. The teeth are specialized structures adapted for mastiquer food. Defenses, which are molars projected beyond the Lèvre S, evolved/moved starting from the teeth and give to certain species an evolutionary advantage . The teeth of the majority of the mammals consist of a root and a cover.

The teeth and defenses have the same structure: Pulp, Dentine, Cement and enamel. The internal part is the cavity of the pulp which is an empty space in the tooth, and which is moulded on the shape of pulp.

The odontoblastic cells are aligned on the cavity of pulp and are responsible for the production of the dentine. The dentine, which are the main component of the objects out of carved ivory, form a layer constant thickness around the cavity of pulp and constitutes the mass of it.

The dentine is a mineral-bearing connective fabric with an organic matrix of Protéine S of Collagène. The inorganic component of the dentine is the Dahllite. The dentine contains a microscopic structure called Tubule dentinal: in fact microchannels radiate towards outside by the dentine starting from the cavity of pulp to the external border of cement. These channels have different configurations according to the ivories and their diameters lie between 0,8 and 2,2 Micromètre S. Their length is determined by the ray of defense. The three-dimensional configuration of the tubule dentinal is genetically given and is thus a characteristic specific to the biological order.

The ivory teeth and defenses can be cut in an almost infinite variety of forms and objects. Some examples of objects cut out of ivory: small statues, Netsuke S, jewels, handles of dishes and plates, incrustations of pieces of furniture and keys of piano. Moreover, defenses and the teeth of the Phacochère, Cachalot, épaulard and Hippopotame can also be dug or cut on the surface, thus preserving their original forms like objects morphologiquement recognizable.

Exploitation

The ivory was always an invaluable material.

The museum of Dieppe presents an important collection of objects suculptés out of ivory.

Because of its animal origin, the ivory recovery constituted a true threat for the species which are equipped with it. The elephant S were particularly driven out for their defenses, so much so that in certain areas of Africa and Asia, their genetic inheritance would be evolving/moving: since only the elephants not having defenses are left in life, these last are disappearing, quite simply.

Regulation on the ivory of elephants

Because of the decline of the populations of producing ivory animals, the ivory importation and sale prohibited or are severely regulated in many countries. There exists a moratorium on the trade of the ivory since 1990.

Substitute and imitations

The low availability of the ivory encouraged the guards of the elephants and the forgers to develop techniques pushed to imitate the ivory.

Fossil ivory

The Fossil ivory of Mammoth, abundant in Siberia, is also used as replacement with the ivory of the currently alive species.

Vegetable ivory

Sometimes, it is absolutely necessary to find a substitute natural that he is animal or vegetable. One uses as follows: vegetable Ivory (Tagua, corozo), horn helmet of the Cockatoo, wood, bone, Fossil resin of Copal ),

The seeds of certain plants - vegetable Ivory - gain in popularity like replacement of the ivory although their dimension limits their uses.

Associations ecologists recommend the use of a natural substitute to the ivory named " Ivory végétal" , resulting from the Equitable trade.

Celluloid

The techniques of the forgers call sometimes upon plastic to obtain more convincing imitations (assembly under pressure of plates of Cellulose, plastic moulding) that the simple mouldings with the Plâtre coats with a product containing Cire.

Ivorine

Without being really an imitation, the Ivoirine is reconstituted ivory. The ivory remains resulting from the size of the objects are reduced out of powder and mixed with a binder. The mixture thus obtained - bread dough kind will be cast in a mould.

By its aspect smoothes and impossibility of determining the percentage of ivory powder present in the part (without destroying it) make that the objects out of ivorine are related with objects in celluloid.

Os

The bone by its close aspect has that of the ivory was always a cheap substitute of the ivory. But with time the bone - of ox and camel mainly yellows and its structure does not make it possible to carry out objets d'art as finely carved as those out of ivory.

Carved ivories

Europe

Far East

Expressions

a Ivory tower , it is a retirement where somebody isolates itself who refuses any contact or any engagement.
a carries ivory , it is the door of the dreams misleading (borrowed by Énée to leave the underground world in the Énéide of Virgile).

Symbolic system

The Noces of ivory symbolize the 14 years of Mariage (62 years according to the versions) in the French folklore.

See too

ivory|ivory

Ivory Barberini, Byzantine objet d'art preserved at the museum from Louvre in Paris.
consular Diptych, late or Byzantine Roman objet d'art
the Ivory Coast, country of Western Africa.

Simple: Ivory

Random links:

Christian-Jaque | List publications by editors - Dargaud - I | Morancourt | Canton of Clermont-Ferrand-North | Quiet character