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Tortoiseshell or tortoise shell is a material produced from the shells of the larger species of
tortoise Tortoises () are reptiles of the family Testudinidae of the order Testudines (Latin: ''tortoise''). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like oth ...
and
turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...
, mainly the hawksbill sea turtle, which is a critically endangered species according to the IUCN Red List largely because of its exploitation for this trade. The large size, fine color, and unusual form of the hawksbill's
scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s make it especially suitable. The distinctive patterning is referred to in names such as the
tortoiseshell cat Tortoiseshell is a cat coat coloring named for its similarity to tortoiseshell material. Like calicoes, tortoiseshell cats are almost exclusively female. Male tortoiseshells are rare and are usually sterile.Atkins (2003), p.105 Tortoiseshell c ...
, several breeds of guinea pig, and the common names of several species of the butterfly genera ''
Nymphalis ''Nymphalis'', commonly known as the tortoiseshells or anglewing butterflies, is a genus of brush-footed butterflies. The genera '' Aglais'', ''Inachis'', ''Polygonia'' and '' Kaniska'', were sometimes included as subgenera of ''Nymphalis''
'' and ''
Aglais ''Aglais'' is a Holarctic genus of brush-footed butterflies, containing the tortoiseshells. This genus is sometimes indicated as a subgenus of ''Nymphalis ''Nymphalis'', commonly known as the tortoiseshells or anglewing butterflies, is a ge ...
'', and some other uses.


Uses

Tortoiseshell was widely used from ancient times in the North and in Asia, until the trade was banned in 2014. It was used, normally in thin slices or pieces, in the manufacture of a wide variety of items such as
comb A comb is a tool consisting of a shaft that holds a row of teeth for pulling through the hair to clean, untangle, or style it. Combs have been used since prehistoric times, having been discovered in very refined forms from settlements dating ba ...
s, small boxes and frames, inlays in furniture (known as Boulle Work carried out by André-Charles Boulle), and other items: frames for spectacles, guitar picks and knitting needles. Despite being expensive, tortoiseshell was attractive to manufacturers and consumers because of its beautiful mottled appearance, its durability, and its organic warmth against the skin. The initial processing involved separating the layers of the scutes from the animal's carapace by heating, softening the plates by boiling them in salt water and flattening them under a press. Two pieces could be fused by use of a hot iron, but like the earlier stages, great care had to be taken not to lose the color. Finishing and polishing was done by various techniques mainly in Europe or in the US. Craftsmen in various Asian countries have also perfected this art.


Availability

In 1973, the trade of tortoiseshell worldwide was banned under
CITES CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
(the Convention on International Trade in Endangered Species). The material was already often imitated in stained
horn Horn most often refers to: *Horn (acoustic), a conical or bell shaped aperture used to guide sound ** Horn (instrument), collective name for tube-shaped wind musical instruments *Horn (anatomy), a pointed, bony projection on the head of various ...
,
plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
like
cellulose acetate In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and ...
, and other materials. The synthetic
Delrin Polyoxymethylene (POM), also known as acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. As with many other synthetic pol ...
has been used especially for guitar picks.
Brand A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create ...
s of synthetic substitutes for tortoiseshell include Tortoloid and Tor-tis.


History

Tortoiseshell has been used since ancient times, and the ancient Greek chelys or lyre often used a whole shell to form its body. Inlaid veneers of tortoiseshell were popular with wealthy ancient Romans for furniture, especially couches for dining, and for small items. The ''
Periplus of the Erythraean Sea The ''Periplus of the Erythraean Sea'' ( grc, Περίπλους τῆς Ἐρυθρᾶς Θαλάσσης, ', modern Greek '), also known by its Latin name as the , is a Greco-Roman periplus written in Koine Greek that describes navigation and ...
'', probably a work of the 1st century AD, distinguishes between shell from different species, with the best regarded as the hawksbill. André Charles Boulle (1642-1732),
cabinetmaker A cabinet is a case or cupboard with shelves and/or drawers for storing or displaying items. Some cabinets are stand alone while others are built in to a wall or are attached to it like a medicine cabinet. Cabinets are typically made of wood (s ...
to
Louis XIV of France , house = Bourbon , father = Louis XIII , mother = Anne of Austria , birth_date = , birth_place = Château de Saint-Germain-en-Laye, Saint-Germain-en-Laye, France , death_date = , death_place = Palace of ...
introduced or perfected
marquetry Marquetry (also spelled as marqueterie; from the French ''marqueter'', to variegate) is the art and craft of applying pieces of veneer to a structure to form decorative patterns, designs or pictures. The technique may be applied to case fur ...
combining thin inlays of tortoiseshell backed with metal, with woods and metal, a style still called after him ( Boulle work). Small luxury objects such as
snuff-box A decorative box is a form of packaging that is generally more than just functional, but also intended to be decorative and artistic. Many such boxes are used for promotional packaging, both commercially and privately. Historical objects are u ...
es were decorated in piqué work, inlays of precious metals and jewels into tortoiseshell (or other materials). Hopes of capturing a large store of tortoiseshell led to the
Ngatik massacre The Ngatik massacre took place over two days of fighting on the atoll of Sapwuahfik in the Micronesian island chain in July 1837. Captain C. H. Hart and his crew of beachcombers of the trading cutter ''Lampton'' from Sydney, Australia, massacred as ...
by Australian "beachcombers" of up to 50 men of
Sapwuahfik Sapwuahfik, formerly Ngatik, or the Raven Islands is a atoll of the Federated States of Micronesia. It is a village and municipality of roughly 430 people on a land area of in the state of Pohnpei. Geography It is located southwest of the m ...
in
Micronesia Micronesia (, ) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and ...
in July 1837.


Notes


References

* Casson, Lionel, "Periplus Maris Erythraei: Notes on the Text", ''The Journal of Hellenic Studies'', Vol. 102, (1982), pp. 204–206
JSTOR
* Caunes, Lison de, and Jacques Morabito. 1997. L’écaille ortoiseshell Dourdan: Vial. * "Transactions", "On Horn and Tortoiseshell", ''Transactions of the Society, Instituted at London, for the Encouragement of Arts, Manufactures, and Commerce'', Vol. 52, PART II (1838-1876), pp. 334–349,
Royal Society for the Encouragement of Arts, Manufactures and Commerce The Royal Society for the Encouragement of Arts, Manufactures and Commerce (RSA), also known as the Royal Society of Arts, is a London-based organisation committed to finding practical solutions to social challenges. The RSA acronym is used m ...

JSTOR
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