Back

Ivory

 

IVORY

This article contains detailed identification information for identifying several different types of ivory, and discuses test methods for determining genuine ivory. Ivory is an animal byproduct; there are as many different kinds of ivory as there are animals with teeth. 

Essentially, ivory is teeth; it's animal teeth. Genuine ivory items were once plentiful. Until quite recently, items made from ivory were readily found at yard sales and online auctions. Unfortunately, online marketplaces have banned ivory due to political issues and it has essentially disappeared from open selling on secondary markets. Genuine antique ivory is rarely seen on these venues now and fewer professional dealers have first hand experience with ivory identification. 

In the photo galleries on the bottom of this page are examples of genuine antique ivory pieces all over 100 years of age. The tongue depressors and letter openers came from France. The bird and Okimono man came from Japan. The napkin ring and Imperial Couple sash retainers came from China. 

Scroll down to see:
Fine Carved Ivory Bird Antique Okimono Japan XIXe Siècle
Fine Carved Ivory Antique Okimono Farmer Japan XIXe Siècle
Carved Ivory Napkin Ring Lychees on Branch Antique Chinese XIXe Siècle
Fine Pair Carved Ivory Antique Imperial Couple Sash Retainers Chinese XIXe Siècle
Deux Abaisse-Langues de Médecin anciens plus un Coupe-Papier XIXe Siècle

REFERENCES
Comprehensive books on ivory identification are also very rare and mostly out of print. Here are three reference recommendations but unfortunately, you'll have to search for them as they're currently out of print.

WILLS, Geoffrey  IVORY  AS Barnes & Co. Publishers. First American Edition. Hardcover, 95 pgs. Indexed. Ivory identification, care, and use around the world. Many black and white photographs and line drawings. 

SHELL, Harvey IS IT IVORY?  Ahio Publishing Co., 1983. Paperback.

ESPINOZA, E.O. IDENTIFICATION GUIDE FOR IVORY AND IVORY SUBSTITUTES  2nd Edition. World Wildlife Fund publishers, 1992. Paperback.


IDENTIFYING DIFFERENT TYPES OF IVORY
Ivory is an animal byproduct; there are as many different kinds of ivory as there are animals with teeth.  Essentially, ivory is teeth, animal's teeth. Ivory can come from the tusks of elephants, from mammoths, Odontoceti (whales with teeth) or any other animal with teeth. Chemically similar to bone and antler, ivory is a collagen matrix with a mineral component, however, ivory is denser than bone because ivory has no blood vessel system. The most commonly found ivories in North America come from elephant, walrus, sperm whale, and hornbill. They're all structurally different so it's possible to identify each as distinct from the others. Most ivory identification is based on examining for specific attributes that are present in the various layers making up the ivory. By slicing away a piece of the ivory at an angle, called a 'cross section', and examining the ivory at this angle, it's possible to discern nature's layering that makes the ivory the specific and distinctive kind that it is.  However accurate cross section examination might be, it isn't always practical for an antiquities dealer to slice and dice their objects d'art. A far more cost effective method of identification is to simply memorize the few visually prominent structural features that determine authentic ivory, along with those unique features that differentiate one type of ivory from another.


ELEPHANT IVORY
Elephant Ivory is the most commonly found ivory and includes ivory from both Indian and African elephants, as well as ivory from mammoths and mastodon. This ivory comes from their tusks, or upper incisors. It is huge compared to other types of ivory, and can have cross sections of up to 20 cm // 8 inches; the length can be up to 2.5 meters // approximately 3 yards. These cross sections are oval and made of dentin, a hard, dense tissue of 70% inorganic material and 30% collagen. One-third to one-half of an elephant tusk is hollow; these tusks don't have the enamel coating that human teeth have. They do, however, have a cementum layer, referred to as the 'bark' or the 'rind', and this is occasionally retained on a piece of worked ivory. 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 in the cross section. They're called the Lines of Owen. When this ivory is cut lengthwise, these lines appear triangular. The lines are fine and even near the hollow of the tusk (the pulp cavity), but closer to the outside of the tusk, they become wavy, with milky areas between them.  Unique to elephant ivory are fine intersecting lines known as the Lines of Retzius. These fine intersecting lines are visible in cross section, and give an engine-turned effect, as 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, for use as inlay, marquetry, veneer and for piano keys. It can be carved finer and more delicately than bone. This type of ivory is porous, and often painted, stained, dyed, and gilded. When cut, the pores of the ivory fill with an oily substance, which helps the ivory polish up nicely.


HIPPO IVORY
Hippopotamus Ivory is the second most commonly found ivory. It comes from the lower canines and incisors of hippos, and is often used for flat item such as buttons and inlay. The size varies, depending on the size of the animal. The lower canine  has a triangular cross section when curved; 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 Hippopotamus  species, and can 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 and is less prone to decay than elephant ivory. 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; hippo ivory has concentric rings in cross section. 

WALRUS IVORY
This ivory comes from the upper canines of walrus. It is oval in cross section, and can be over 2 feet in length. It has an inner dentin layer which has a high mineral content that forms as the tusk grows, leaving a marbled look on finished objects. There is an outer dentin layer, and a smooth, dense cementum layer. Walrus ivory is used primarily for small objects.

SPERM WHALE  IVORY
Thirty teeth of the sperm whale can be used for ivory. Each of these teeth, up to 8" long and 3" across, are hollow for the first half of their length. Sperm whale ivory is easily confused with walrus ivory, as both have two distinct layers. The inner layer of sperm whale ivory is much larger that walrus ivory, and in a longitudinal section, sperm whale dentin has yellow "globules" in the marbleizing. 

HORNBILL IVORY
Hornbill ivory comes from the casque or epithema of the Helmeted Hornbill, a bird native to the East Indies. The epithema  is a horny excrescence on the bill of some birds (such as the casque of the a hornbill).  Hornbill ivory can be distinguished from the rest of its'  Bucerotidae family.  The front of its almost vertical and slightly convex epithema is  made of a solid mass of horn. This "horn" or "ivory" is quite hard, dense, and closely-textured. This substance is used to make small objects such as buckles and brooches, and is highly valued by the Chinese. A bright yellow interior with a scarlet rim is visible in cross section.

VEGETABLE ' IVORY'
Vegetable ivory is completely made of cellulose rather than collagen and comes from the inner seed of the South American ivory palm, whose seeds are the size and shape of a small hen's egg, very hard, and completely solid. Vegetable ivory is smooth, takes a good polish, easily absorbs dyes, and is relatively inexpensive. It is primarily used for small items such as dice and buttons. Since World War II, vegetable ivory has been largely replaced by plastics.

SYNTHETIC 'IVORY' 
Alexander Parkes invented celluloid in 1865; both celluloid and casein became excellent and popular ivory substitutes. Common names for  'faux' ivories include, but aren't limited to French Ivory, Genuine French Ivory, Ivoride, and Ivorine.  These synthetic materials are generally quite smooth and regular. The grain patterns and engine-turned effects, that are characteristically irregular in genuine ivory,  are simply added to these synthetic materials as part of their manufacturing process. 

TESTS FOR FAUX 'IVORY' VERSUS REAL 'IVORY'
Manufacturing refinements and improvements process synthetic imitations using celluloid, and some vegetable ivories, to be remarkably similar to genuine ivory. Even with substantial experience, it can be difficult to tell at first glance that these are fakes. Genuine ivory, while denser than bone, is not particularly heavy, and fakes are deliberately designed to be similar in weight, color, textures, and apparent density. Various tests are often needed to identify fakes and determine their composition. While chemical tests are excellent, they're also destructive, and they're not exactly do-it-at-home science. There is a simple test, known as the 'hot pin' test, that can be done at home, and when performed correctly, it is a definitive test for the vast majority of synthetic replicas; it can determine if a piece has a plastic or faux vegetable nut 'ivory' component. The test is based on the fact that most plastics will melt, and most vegetable nuts will burn, even though the exact temperature required to melt or burn them varies based on their composition.

THE HOT PIN TEST
Here are instructions for the hot pin test.  You will need a safety pin or dress pin, with a sharp point,  and you will need a candle.  Take the safety pin or dress pin, light the candle, and hold the tip of the pin directly inside the lit candle flame wick, until you see the tip of the pin turn black (that's carbon).  You must heat the pin thoroughly to this point, quickly wipe off the black carbon with a folded dry paper towel (watch out, the pin is HOT, and don't burn yourself), and then immediately, quickly,  pierce the item with the hot pin tip, preferably on the underside where a melted or burned result won't mar the piece. Pierce with the pin as hot as possible, but if you don't wipe the pin, you risk transferring the carbon black to the piece. You may need to hold the tip of the pin to the material for a few seconds before anything occurs, and you may need to press the pin tip  gently into the material.

 If nothing at all happens after several seconds, the pin tip may not have been sufficiently hot; if the pin tip wasn't hot enough, you won't get a definitive result one way or the other, and you may need to repeat this procedure. The tip must be as hot as possible using the lit candle; the lit candle generates sufficient heat to char most metal pins and it isn't necessary or useful to try this using other heat sources. If there is any give to the material at all when you pierce it with the hot tip, the material has a plastic component that is melting under the heat of the pin tip.  If there is any burning or cooking smell to the material at all when you do this, the material likely has a vegetable nut component. 

BAKELITE
Some Bakelite plastics were also manufactured to resemble ivory. Bakelite has an usual composition; the materials used in its' manufacturer cause it to emit a characteristic odor in response to friction or heat.  Bakelite will emit this odor when friction is applied to it, for example, by rubbing it back and fourth on your pants leg until you feel the piece is heating up and getting warm to the touch in your hand,  or run it under very hot tap water for a full minute. Then smell it immediately; you're smelling the odor of La Brea Tar Pits petroleum byproducts. 

Most plastics will melt or burn, vegetable nuts will burn, and heating a pin thoroughly, and then puncturing plastic carefully with the hot pin tip, will almost certainly be a decisive test for the vast majority of these synthetic and vegetable-based replicas.  Even melamine resin can burn from hot pin applied concentrated heat, in spite of being marketed as ashtrays impervious to lit cigarettes. Isn't Science wonderful??!

And now, for something completely different... 
HOW WE TESTED IT TO SEE IF IT'S IVORY
1:  We sawed it in half and tried it on an elephant.
2:  When it was made, plastic didn't exist, so that's why they used ivory.
3:  We took it to Los Alamos and had it neutron activated in their test reactor. The gamma ray spectrum is consistent with a homogeneous ivory construction and inconsistent with non-biological material.

 

Fine Carved Ivory Bird Antique Okimono Japan XIXe Siècle

 

 

 

 

 

 

 

Fine Carved Ivory Antique Okimono Farmer Japan XIXe Siècle

 

 

Carved Ivory Napkin Ring Lychees on Branch Antique Chinese XIXe Siècle

 

Fine Pair Carved Ivory Antique Imperial Couple Sash Retainers Chinese XIXe Siècle

 

Deux Abaisse-Langues de Médecin anciens plus un Coupe-Papier XIXe Siècle

 

 


We hope this information is helpful to you. Thanks for reading. Merci de votre visite.

 

 

 


 


All Content is © Debra Spencer, Suit Yourself™ International. Technical Library FAQ Index ISSN 2474-820X. All Rights Reserved.
Please do not reproduce in part or in whole without express written consent. Thank you.

 

Top
All Content is ©2019 Debra Spencer, Appanage™at www.suityourself.international Suit Yourself ™ International, 120 Pendleton Point, Islesboro Island, Maine, 04848, USA 44n31 68w91 Technical Library FAQ Index ISSN 2474-820X. All Rights Reserved. Please do not reproduce in part or in whole without express written consent. Thank you.

Read Our Magazine! A Fortune Cookie Once A Week.

Enter your e-mail address to receive our magazine.
Email
Country
Please enter a valid email address.
Email address already subscribed.
All Content is ©2019 Debra Spencer, Appanage™at www.suityourself.international Suit Yourself ™ International, 120 Pendleton Point, Islesboro Island, Maine, 04848, USA 44n31 68w91 Technical Library FAQ Index ISSN 2474-820X. All Rights Reserved. Please do not reproduce in part or in whole without express written consent. Thank you.
Success consists of going from failure to failure without loss of enthusiasm. ~ Winston Churchill