Tortoise shell (or tortoiseshell) 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 made tortoise shell an ideal jewelry material.
Contemporary law has banned the sale and importation of tortoise shell products in the United States and other countries around the world. Sale of unadulterated antique tortoise shell items is allowed.
Gemological Information for Tortoise Shell
| Color: | Mottled Brown, Yellow, Black, White |
| Crystal Structure: | None – Organic |
| Refractive Index: | 1.55 |
| Durability: | Fair |
| Hardness: | 2.5 |
| Family: | |
| 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.