Identifying Different Types of Ivory
Part of the Uniclectica Antiques and Collectibles Online Series "Caring For Your Antiques and Collectibles"
What Is Ivory?
Ivory is the teeth of animals. "True" ivory comes from elephants and mammoth; however, the term is generally applied to the tusks of other mammals, and some synthetics. Chemically, ivory is similar to bone and antler, and comprises a collagen matrix with a mineral component. Unlike bone, ivory has no blood vessel system, and is therefore more dense.
The most commonly found ivories in North America come from elephant, walrus, sperm whale, and hornbill. It is possible to tell these ivories apart, as they are structurally different.
Growth occurs as layer upon layer of calcified tissue is deposited on the interior of the tusk; you can see these concentric oval growth lines (called the Lines of Owen) in cross section. If you cut ivory lengthwise, these lines appear triangular. Fine and even near the hollow of the tusk (the pulp cavity), these lines become wavy and have milky areas between them as you get closer to the outside of the tusk.
Unique to elephant ivory are the Lines of Retzius. These fine intersecting lines are visible in cross section, and give an engine-turned effect (intersecting lines with a diamond shape between them).
Generally, elephant ivory has a fine, even grain and is easily carved in all directions. It can be thinly cut (i.e. for piano keys), and can be more deltcately carved than bone. This ivory is often painted or stained, dyed, and gilded. When cut, the pores of the ivory fill with an oily substance, which helps the ivory polish up nicely.
2. Hippopotamus Ivory
The lower canine is curved, and has a triangular cross section; the incisor is straighter, and has a circular cross section. Both have two layers of dentin: an outer, primary dentin, and an inner, secondary dentin. The innermost layer has a marbled appearance which differs by species, and can even appear to have a greenish cast. The pulp cavities of these teeth are fairly small. Unlike elephant ivory, hippo ivory does have a thick enamel coating.
Hippo ivory is denser than elephant ivory, harder to carve, and has a finer grain. There is none of the "engine turned" effect in cross section, rather, hippo ivory has concentric rings in cross section. Finally, hippo ivory is less prone to decay than elephant ivory.
3. Walrus Ivory
4. Sperm Whale Ivory
5. Hornbill Ivory
6. Vegetable Ivory
7. Synthetic Ivories
Books Dealing with the Identification of IvoryThere are a few good books dealing with the identification of ivory. I currently have available *very* limited quantities (often single copies only) of the following out of print books (click on the dealer name for ordering information):
IVORY By Geoffrey Wills. Published by AS Barnes & Co. First American Edition. Hardcover, 95 pgs. Indexed. Synopsis: covers ivory identification, care, and uses around the world. Many black and white photographs and line drawings. Condition:Very good in Good dustjacket (some scuffing). UN601 $23.00 Uniques.
The following are currently out of print, but are listed here for your information.
Is It Ivory? By Harvey Shell. Published by Ahio Publishing Co., 1983. Paperback.
Identification Guide for Ivory and Ivory Substitutes 2nd Edition. By E.O. Espinoza. Published by the World Wildlife Fund, 1992. Paperback.
Ivory By Geoffrey Wills. Published by AS Barnes and Co., 1969. Hardcover.