Ivory
Ivory is an organic gemstone made from the elongated tusks of elephants and other large mammals. Key indicators of authenticity include the chrysanthemum-like rosette patterns visible in cross-section and the dark spots found at the tip of the tusk. It has long been valued as a material for carving and inlay work.
Ivory, characterized by its beautiful rosette patterns
Basic Information
| English Name | Ivory |
|---|---|
| Japanese Name | Zoge (Ivory) |
| Chemical Composition | Hydroxyapatite, mainly Ca5(OH)(PO4)3, containing organic matter and moisture |
| Hardness | 2.5 |
| Specific Gravity | Approx. 1.8 |
| Crystal System | Massive, composed of aggregated hexagonal fibrous particles |
Characteristics & Varieties
- Hard Ivory: Hard tusks from African forest elephants.
- Soft Ivory: Softer tusks from savanna-dwelling elephants.
- Bastard Ivory: Tusks with intermediate hardness, such as those from Thailand.
- Vegetable Ivory: Derived from the seeds of palm-family plants such as tagua nuts (corozo nuts) and carolyna nuts.
Origin, Aliases, Treatments & Similar Stones
Primary Origins: Africa, Asia (living species), Siberia (fossil ivory).
Aliases: Vegetable ivory, animal teeth/tusks (hippopotamus, narwhal, whale, wild boar, etc.).
Treatments: Bleaching (using hydrogen peroxide to break down black or gray pigments), dyeing (historically stained pale brown with yaguruma or colored lacquer during the Edo period).
Similar Stones: Bone material (processed deer antlers or bones of large mammals).
Note: International trade in modern ivory is strictly regulated by the 1973 CITES convention; ensuring you have reliable certification is essential when making a purchase.