Tortoiseshell

MFA Acc. #: 17.2233

Description

A semitransparent, mottled brown material obtained from the protective outer shell on some large marine turtles, especially the hawksbill (Eretmochelys imbricata), loggerhead (Thalassochelys caretta) and green turtle (Chelonia mydas). Tortoiseshell is composed of keratin, a fibrous protein. It is slightly flexible and can be heated then molded into various shapes. Tortoiseshell has been valued since ancient times when it was used for rings, bracelets, and musical instruments. Later, it was popular as inlay and veneer. Since the 16th century, it was used to decorate European furniture, often in highly decorative inlay patterns. Tortoiseshell has also been used for boxes, combs, brush handles, pocketknives, and jewelry. Because of its expense, imitations were made from stained horn, and later, with early plastics like celluloid or casein. In 1975, the hawksbill and other sea turtles were declared endangered and international trading in modern tortoiseshell became illegal.

MFA Acc. #: 51.302

Synonyms and Related Terms

tortoise shell; tortoise-shell; turtle shell; carapace; hawksbill (Eretmochelys imbricata); loggerhead (Thalassochelys caretta); green turtle (Chelonia mydas)

Other Properties

When heated, melts to black mass and smells like burnt hair

Density	1.26-1.35

Hazards and Safety

Turns gray in strong sunlight. Susceptible to insects damage

Spur-thighed tortoise Testudo graeca

Additional Information

° G. Hanlon, "Tortoiseshell", The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996. ° Plastics Museum website ° R.Vuilleumier, "Schildpatt--Verarbeitungstechniken und Imitationen", Maltechnik-Restauro, 85, 1979, p.40-47.

Additional Images

• 

  Pond turtle carapace

• 

  Tortoiseshell

• 

  Synthetic tortoiseshell

• 

  Synthetic tortoiseshell

Sources Checked for Data in Record

• The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: G. Hanlon, "Tortoiseshell"

• A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962

• Caring for your Collections, Arthur W Schulz (ed.), Harry N. Abrams, Inc. , New York, 1992

• Oppi Untracht, Jewelry Concepts and Technology, Doubleday & Co., Inc., New York City, 1985

• Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982

• Tom Rowland, Noel Riley, A-Z Guide to Cleaning, Conserving and Repairing Antiques, Constable and Co., Ltd., London, 1981

• Gordon Hanlon, contributed information, 1998

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998