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Condition Reporting

Ivory & Tooth

Drawer full of compartmentalized ivory & bone.
For small items and archaeological materials, it can sometimes be difficult to tell antler from bone from ivory from tooth. If you’re not sure, just describe the features you see and indicate your hesitation with qualifiers like “maybe” “perhaps” “looks like” “could be” “likely” and so forth. The items in the lower left corner of the drawer are certainly teeth. The other items would require closer examination and some might be difficult to determine.

Photo credit: Alaska State Museum

Close-up of end of ivory showing Schrager lines.
“Schrager lines” are diagnostic for elephant, mammoth, and mastodon tusk. Schrager lines are the intersecting V-shaped lines in the cross section of tusk. Some people say they look like “engine turnings.” If the v-shapes near the outer surface of the tusk are greater than 90 degrees (an obtuse angle) it’s probably elephant ivory. If the angle is less than 90 degrees (acute, like a gothic arch) that indicates mammoth or mastodon ivory. This item pictured is the end of a bowl carved from mammoth or mastodon tusk.

Photo credit: Sheldon Jackson Museum collection SJ-II-K-115

2 tusks.
Mammoth and mastodon tusks can come in a variety of colors, usually depending on the burial conditions. Occasionally the chemistry of the burial will give blueish streaks of a mineral called “vivianite” but that’s not the case in this image.

Photo credit: Alaska State Museum collection

3 people evaluating large tusks on a table.
Sometimes tusks have a coarser outer layer present, but it is often cracked. The lighter tusk in the middle of this pile no longer has this outer layer.

Photo credit: Alaska State Museum collection

Close-up of end of bone showing spiral-like cracking.
Ivory and tooth have both mineral components and organic components. This makes them sensitive to changes in humidity, since the organic components can shrink and swell but the mineral components do not. Cracking in concentric layers is commonly seen in tusk.

Photo credit: Alaska State Museum collection 2017-2-1

Close-up of end of ivory that has some charring.
This image shows ivory that has been burned a little bit.

Photo credit: Alaska State Museum collection

Darkened carved ivory.
This archaeological object, likely made of ivory, has a darkened surface and is delaminating, delicate, and slightly crumbly at the areas of loss. This kind of damage is not uncommon, and has often been treated by consolidating the material with diluted adhesives. This often gives a slightly glossy appearance. Try to find any associated treatment information about archaeological material. The older the excavation or collection of that material, the less likely it was to have its treatment documented. Unfortunately, less stable substances were often used in the past to try to preserve damaged objects, and in order to re-treat the object with something more stable it helps greatly to know what was used in the first place.

Photo credit: Alaska State Museum collection II-A-4508

Ivory cribbage board with broken bits.
Items made from walrus tusks are common in Alaskan collections. Cribbage boards made from tusks have long been a popular tourist item. Carved figures attached to tusks are vulnerable to damage from mishandling, and pegs are often lost.

Photo credit: Sheldon Jackson Museum collection SJ-II-Y-132

Close-up of ivory cribbage board.
The end of this cribbage board tusk has a special compartment with a hinged door to store the various cribbage pegs. Document these carefully, as they are easily dissociated.

Photo credit: Alaska State Museum collection 98-7-213

Carved tusks to depict walrus heads.
Ivory is porous and can become stained or discolored. This carved tusk shows an old yellowish-brown adhesive where it was broken and repaired. Old adhesives can sometimes become weak and brittle, and tusks are heavy. Beware old repairs, and look for records to indicate what was done.

Photo credit: Alaska State Museum collection II-A-2789

Beaver skull.
Animal skulls often still have teeth in them, but unless they have been adhered in place they are often loose. If you are condition reporting a skull, indicate if there are any missing teeth, and if the teeth present are loose. Beaver and porcupine teeth typically have this kind of orange surface due to iron, which makes this surface enamel harder than the whiter tooth areas, and thus allows them to self-sharpen. The back teeth of this animal have black staining, which should be noted. Herbivores are more likely to have stained teeth than carnivores.

Photo credit: Alaska State Museum collection 2014-4-13

Broken tooth (porcupine or beaver).
Teeth tend to crack easily, and are sensitive to changes in humidity. If a tooth breaks, the pieces often do not fit back together perfectly, especially if the tooth had been previously cracked.

Photo credit: Alaska State Museum collection 2003-1-17

Close-up of bear teeth within its skull.
The more porous, irregular-looking bone around the roots of these teeth suggest the bear might have had infection in those areas. Perhaps it was an older bear. There is staining on the teeth, and the lower canine has some loss of enamel on the inner surface.

Photo credit: Alaska State Museum collection 2014-4-16

Mammoth tooth.
This is a mammoth tooth. This kind of tooth is often delicate and might suffer from cracking and coming apart in layers. Because of this vulnerability, it is also common for teeth to been repaired, consolidated or coated. Look for treatment records if you can find them. Beware handling these teeth. Since they are fragile but also heavy, they are prone to handling damage.

Photo credit: Alaska State Museum collection 98-7-331

Mastodon tooth.
Mastodon teeth look different from mammoth teeth because of these cone-shaped cusps, better for chewing up woody bushes and similar forage. This tooth has several large open cracks, and some loss of the tip of one cusp. Sometimes mammoth and mastodon teeth are sub-fossilized, or in the process of becoming mineralized into true fossils but not yet fully stone.

Photo credit: Alaska State Museum collection IV-C-59

2 cracked seal teeth held up by a gloved hand.
These are seal teeth with very significant, open, longitudinal cracks.

Photo credit: Alaska State Museum collection I-B-167

Ivory Madonna figure.
This Madonna figure is carved from a walrus tusk, as evidenced from the cross section visible from the base. You might be able to see a slight pinkish tone. Because ivory is prone to crack, some carvers and collectors have different techniques to try to prevent that issue, including soaking the tusk in various kinds of oils and other substances. This sometimes gives the tusk a slight color.

Photo credit: Alaska State Museum collection 2011-12-2

End view of walrus tusk that has a gaping crack in the cross section.
This is a cross section of walrus tusk, showing the telltale inner core (looking like oatmeal or marble) of secondary dentine, surrounded by primary dentine, and a thinner outer layer sometimes called a “transition ring”. I think this ring is neither dentine nor cementum, but here we reach my limits…the inner core appearance is what is helpful for our purposes.

Photo credit: Alaska State Museum conservation research collection

Cut walrus tusk with carvings on the inside.
The upper edge of this artifact shows the telltale secondary dentine that tells us this item is walrus ivory, here engraved with a whale hunting scene.

Photo credit: Alaska State Museum collection II-A-5

Crumbling & flaking ivory carving.
Our database describes this item as made from ivory. A condition report ought to indicate the surface is stained dark brown and one side has severe delaminating, flaking, and crumbling. Up to 40% of the edge has been lost, and there are protrusions that suggest they are damage attachment points for further features now lost.

Photo credit: Alaska State Museum collection II-A-6956

Shark teeth made into earrings.
One of these shark teeth has vertical cracks with some dark stain, as well as some discoloration on the upper half of the tooth. Overall, however, these earrings are stable (and spectacular!)

Photo credit: Alaska State Museum collection II-B-981