Tortoise shell is the name for the outer blades covering the upper shell of the Hawksbill turtle and the Loggerhead turtle. Tortoise shell has been valued for use in jewelry since Roman times. Combs, bracelets, earrings, cameos and decorative inlay have all been made from tortoise shell. The ability to use heat for shaping makes tortoise shell an ideal jewelry material.

Gemological Information for Tortoise Shell

Color:	Mottled Brown, Yellow, Black, White
Crystal Structure	None - Organic
Refractive Index:	1.55
Durability:	Fair
Hardness:	2.5
Similar Stones:	Horn and Plastic
Treatments:	Dyeing and Lamination
Country of Origin:	Brazil, Caribbean, East Indies, Indian Ocean, Pacific Ocean Note: Illegal to import into the U.S.

Tortoise Shell Care

Ultrasonic Cleaning:	Never
Steam Cleaning:	Never
Warm Soapy Water:	Safe - no brushes
Chemical Attack:	Attacked by Nitric Acid
Light Sensitivity:	May Darken
Heat Sensitivity:	Softens and darkens. When burned-smells like protein.

Sources

• Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 245-246.

• Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 308.