Ivory is dense tooth material, primarily dentine, harvested from the teeth or tusks of several animal species. The word most often conjures images of elephant tusks, and for good reason: African and Asian elephants have historically been the dominant source. But ivory also comes from walruses, narwhals, hippos, sperm whales, warthogs, and even the frozen remains of woolly mammoths buried for tens of thousands of years. Beyond the animal kingdom, plant-based “vegetable ivory” and modern synthetic composites have entered the picture as substitutes. Each type has a distinct origin, structure, and legal status, and telling them apart has become a forensic science of its own.
African and Asian Elephant Tusks
When people say “ivory,” they almost always mean elephant ivory. The tusks of both African elephants (Loxodonta africana) and Asian elephants (Elephas maximus) are continuously growing upper incisors. Their hard tissue is composed of dentine covered by a thin outer layer of cementum, with no enamel coating on the exposed tusk surface.1PubMed Central. Structure and innervation of the tusk pulp in the African elephant (Loxodonta africana) African elephant tusks tend to be larger, sometimes exceeding two meters in length, while Asian elephant tusks are generally smaller and, in many populations, only males carry them at all.
The internal structure of elephant dentine gives the material its trademark appearance. When you cut an elephant tusk in cross-section, you see a pattern of intersecting arcs known as Schreger lines, sometimes described as an engine-turned or crosshatch design. These lines are unique to elephant-family ivory and serve as one of the primary ways experts distinguish elephant ivory from other types. The angle at which these arcs intersect differs between African and Asian elephants, and between elephants and mammoths, giving forensic analysts a reliable visual fingerprint even in carved objects where external shape has been lost.
International trade in elephant ivory from animals killed after 1989 is banned under the Convention on International Trade in Endangered Species (CITES). Despite the ban, illegal poaching and trafficking persist, which is why forensic identification tools have become so critical. The sheer volume of seized ivory in recent decades has driven investment in DNA-based and chemical methods for pinpointing where a tusk was taken from and when the animal died.
Mammoth Ivory From the Permafrost
Woolly mammoths (Mammuthus primigenius) went extinct thousands of years ago, but their tusks survive in remarkable condition in the permafrost of Arctic regions. These fossil tusks have become a significant commodity on the global gemstone and luxury-materials market. The primary source is Northern Yakutia, a region in Russia’s Far East, where permafrost conditions have preserved mammoth remains for millennia. Industrial-scale deposits of mammoth tusks are concentrated in just a few Arctic zones, and Northern Yakutia is the only region today with confirmed recoverable resources of fossil mammoth ivory.2Arctic and Antarctic Research. Prospects of using unmanned aerial vehicles for detecting fossil mammoth ivory fields in the Arctic
The tusks emerge as permafrost erodes, a process driven by thermal erosion along riverbanks and coastlines. The original deposits are essentially cryogenic bone reservoirs locked in ice. As warming temperatures and natural erosion expose these layers, new accumulations of tusks become accessible. Collectors and commercial operations recover them from exposed sediment, riverbeds, and coastal bluffs.
Mammoth ivory closely resembles elephant ivory at first glance, which creates both opportunities and problems. On the opportunity side, mammoth ivory is legal to trade in most countries because the animals are long extinct and no living population is threatened. On the problem side, this legal status has been exploited as a laundering pathway: illegal elephant ivory has been misrepresented as legal mammoth ivory to evade CITES restrictions. Distinguishing the two requires either microscopic examination of Schreger line angles, which tend to be more acute in mammoth ivory than in modern elephant ivory, or laboratory analysis.
The material itself is almost entirely dentine, with a relatively small pulp cavity at the base and no enamel covering. Craftsmen have worked mammoth ivory for centuries, prizing what carving specialists describe as its mesh-like internal structure. This structure gives the material hydroscopic properties: it absorbs and releases moisture, swelling when wet and shrinking when dry. Artisans traditionally exploit this by soaking tusks in water to make the ivory more supple and easier to carve.3Berghahn Journals. Mammoth Ivory and Craftsmen’s Work
Hippopotamus Ivory
Hippo ivory comes from the large lower canine teeth and incisors of the common hippopotamus (Hippopotamus amphibius). These teeth grow continuously and can reach substantial size, with the lower canines sometimes exceeding 50 centimeters in length. Hippo ivory has been traded and carved for centuries, and in some periods of history, it was actually preferred over elephant ivory for certain applications because of its denser, harder composition and brilliant white color that resists yellowing.
Under the microscope, hippo ivory looks quite different from elephant ivory. The most distinctive feature is a pattern of straight, repeating parallel growth bands that cross the cut surface. On other planes, a wave-like micro-topography appears, created by dentinal tubules that traverse the dentine matrix in a helicoidal, or spiral, arrangement.4bioRxiv. Archaeological Ivories: A practical guide for identifying elephant and hippo ivory in the archaeological record The hippo incisor, which is less commonly encountered in carved objects, shows concentric growth bands instead. These patterns are so distinct from the Schreger lines of elephant ivory that trained analysts can usually identify the species with a simple magnifying lens at moderate magnification.
Hippo ivory fell under CITES regulation after hippo populations declined sharply in parts of Central and East Africa. Some researchers have noted that when elephant ivory bans tightened, demand for hippo ivory increased as traders looked for legal alternatives, putting additional pressure on hippo populations. Today, international trade in hippo ivory requires CITES permits and is subject to country-specific restrictions.
Marine Mammal Ivory
Several marine mammals produce tusks or teeth that qualify as ivory. The most distinctive is the narwhal (Monodon monoceros), an Arctic whale whose single spiraling tusk can grow to nearly three meters. This tusk is actually an elongated upper left canine tooth that erupts through the lip and grows in a left-handed helix. What sets the narwhal tusk apart from every other form of ivory is that it functions as a sensory organ. The tusk contains millions of open dentinal tubules that run from the outer cementum surface all the way to the inner pulp. Ocean water enters through porous cementum channels and reaches nerve endings near the pulp, and the sensory signal travels through the maxillary branch of the fifth cranial nerve to the brain.5PubMed. Sensory ability in the narwhal tooth organ system
Researchers have confirmed this sensory ability by exposing the tusk surface to alternating solutions of saltwater and freshwater and measuring significant changes in the animal’s heart rate. The implication is that narwhals can detect changes in water salinity, temperature, or pressure through their tusks, a finding that upends the old assumption that the tusk was purely a display weapon for male competition. Evidence from unerupted tusks, female erupted tusks, and vestigial teeth suggests the sensory architecture is a deep evolutionary feature rather than a secondary adaptation, and differences in foraging behavior between males and females support the idea that the tusk serves a genuine ecological function.
Walrus ivory, sourced from the elongated upper canine teeth of the Pacific and Atlantic walrus, has been used by Indigenous Arctic peoples for tools, art, and trade for thousands of years. Walrus ivory is denser than elephant ivory and has a distinctive secondary dentine core, sometimes called oosik or “walrus opal,” that shows a granular, marbled texture in cross-section. This core is instantly recognizable and makes walrus ivory relatively easy to identify even in finished objects.
Sperm whale teeth also fall under the ivory umbrella, though they are smaller and have been used primarily for scrimshaw, the art of engraving and inking designs on polished tooth surfaces. Trade in marine mammal ivory is governed by a patchwork of international and domestic regulations, including CITES, the Marine Mammal Protection Act in the United States, and various Indigenous exemptions that permit traditional subsistence harvest and craft.
Helmeted Hornbill “Ivory”
Not all materials called ivory are dentine. The helmeted hornbill (Rhinoplax vigil), a large bird found in the rainforests of Southeast Asia, has a solid casque made of keratin sitting atop its bill. Unlike other hornbill species, whose casques are hollow, the helmeted hornbill’s casque is dense and carvable, earning it the nickname “hornbill ivory” or “ho-ting” in Chinese trade. The material is bright red and yellow, takes a high polish, and has been carved into ornaments and snuff bottles for centuries.6BIO Web of Conferences. A molecular genetic approach for sex determination on helmeted hornbill (Rhinoplax vigil) casque: a forensic casework
Despite being keratin rather than dentine, hornbill ivory has attracted serious poaching pressure. The species is now critically endangered, and the illegal casque trade, driven primarily by demand for carved luxury items, has contributed to steep population declines. CITES lists the helmeted hornbill on Appendix I, which prohibits all commercial international trade. Seizures of smuggled casques have been reported across Southeast Asia in recent years, sometimes numbering in the hundreds in a single shipment.
Vegetable Ivory and Synthetic Substitutes
Long before modern synthetics, people found plant-based stand-ins for animal ivory. The term “vegetable ivory” refers to the dried endosperm of seeds from several palm species, most commonly the tagua palm (Phytelephas macrocarpa) native to South America. When dried, tagua nuts become extremely hard, white, and fine-grained, closely mimicking the look and feel of elephant ivory. They can be turned on a lathe, carved, and polished, and they were widely used in the 19th and early 20th centuries for buttons, chess pieces, and small decorative objects. Tagua remains commercially available today and is marketed as an ethical, sustainable alternative.
The first synthetic substitute for ivory appeared in 1869, when John Hyatt developed celluloid, an early artificial plastic, specifically to replace ivory in the manufacture of billiard balls and decorative objects.7Journal of Digital Food, Energy & Water Systems. A Review of Plastic Pollution; Conventional and Recent Bioremediation Technologies Billiard balls had been one of the largest single uses of elephant ivory, and the supply problem was already acute by the 1860s. Early celluloid balls were imperfect: they were prone to chipping and occasionally cracked with a loud pop that reportedly alarmed players. Manufacturers experimented with composite materials combining celluloid with bone to improve performance.8PubMed Central. Best billiard ball in the 19th century: Composite materials made of celluloid and bone as substitutes for ivory These 19th-century substitution efforts represent one of the earliest cases of material science being mobilized to reduce pressure on an endangered animal.
Modern synthetic ivory has moved well beyond celluloid. Researchers have developed a hydroxylapatite-gelatin biocomposite that is chemically identical to natural ivory but engineered with functional properties optimized for specific applications, such as piano key surfaces.9Sustainability. Bio-Inspired Synthetic Ivory as a Sustainable Material for Piano Keys Hydroxylapatite is the same mineral that makes up the inorganic component of natural dentine, and gelatin mimics the collagen matrix, so the resulting material replicates ivory’s texture, moisture response, and tactile qualities without any animal source. Piano manufacturers, who once consumed significant quantities of elephant ivory for key coverings, have largely transitioned to synthetic alternatives, and Steinway and other major makers stopped using natural ivory decades ago.
How Forensic Scientists Identify and Trace Ivory
With so many types of ivory in circulation, and with illegal elephant ivory sometimes disguised as legal mammoth or hippo ivory, forensic identification has become a multi-layered discipline. The simplest method is visual and microscopic examination: Schreger line angles for elephants and mammoths, parallel growth bands for hippos, granular core patterns for walrus. But when ivory has been carved, powdered, or otherwise processed beyond recognition, analysts turn to more advanced tools.
One technique uses infrared spectroscopy to distinguish ivory from bone and from resin-based fakes. The method works even on powdered samples that have lost all visual features, and it can differentiate genuine ivory from synthetic imitations through comparison of spectral signatures.10PubMed. Ivory or Bone? discrimination using ATR-FTIR spectroscopy and chemometrics This is especially useful at customs checkpoints, where officers may encounter processed ivory in forms that look nothing like a tusk.
For determining where an elephant was killed, two main approaches dominate. DNA analysis uses genetic markers to assign a tusk to a geographic population. One method employs a spatial mapping technique that uses genetic similarities across tusks to infer whether multiple seized samples came from one location or several.11PubMed Central. Using DNA to track the origin of the largest ivory seizure since the 1989 trade ban This has allowed investigators to connect large seizures to specific poaching hotspots in Africa, providing actionable intelligence for enforcement agencies.
Isotopic profiling offers a complementary approach. By measuring the ratios of stable isotopes of carbon, nitrogen, oxygen, hydrogen, and sulfur in ivory powder, researchers can build a chemical fingerprint that reflects the diet, water sources, and geology of the region where the elephant lived. A large-scale study using over 500 ivory samples from 28 African and six Asian elephant range states found that isotopic profiling could assign about half of all samples to within roughly 380 kilometers of their true origin, with most of the remaining samples falling within about 1,150 kilometers.12Elsevier (Biological Conservation). Towards understanding isotope variability in elephant ivory to establish isotopic profiling and source-area determination That resolution is not as precise as DNA in every case, but isotopic analysis works on samples where DNA has degraded, which is common in old or heat-treated ivory.
A third forensic tool, radiocarbon dating, answers a different question: when did the elephant die? This matters because the 1989 CITES ban applies to ivory from elephants killed after that date, but older “antique” ivory can sometimes be legally traded. Radiocarbon measurements exploit the spike in atmospheric carbon-14 caused by nuclear weapons testing in the mid-20th century. By measuring the carbon-14 content of a tusk, analysts can determine whether the animal was alive during or after the bomb-pulse era. In one case study, tusks claimed to have been hunted in the 1960s in Tanzania and Kenya showed radiocarbon values consistent with the 1960-1975 bomb peak, confirming that they pre-dated the ban.13Radiocarbon. 14C Bomb Peak Analysis of African Elephant Tusks and its Relation to Cites This technique has become a standard tool for verifying or debunking claims about the age of seized ivory.
Why Ivory Has Been So Prized
Ivory’s appeal goes beyond aesthetics, though its creamy luster and smooth surface are certainly part of the draw. As a material, dentine ivory occupies an unusual niche: it is harder than wood but softer than stone, which means it can be carved with fine detail using relatively simple hand tools. It holds sharp edges and thin walls without cracking the way bone tends to. It takes dye and polish beautifully. And because each tusk is a single continuous piece without grain direction in the way wood has, carvers can work in any orientation without worrying about splitting.
Mammoth ivory’s hydroscopic mesh structure, described earlier, illustrates another dimension of the material’s versatility. An artisan can manipulate its moisture content to make it temporarily pliable, carve it into shape, then let it dry and harden. This property made ivory uniquely suited to objects that require both precision and durability, from piano keys and billiard balls to miniature portrait reliefs and religious figurines.
The cultural value of ivory also varied by type. In East Asian markets, elephant ivory was the gold standard for large carvings and name seals. In Inuit and Yupik communities, walrus ivory carried deep cultural significance and was central to toolmaking and storytelling art. In Southeast Asian markets, helmeted hornbill casque commanded prices per gram that rivaled or exceeded those of elephant ivory, partly because of its rarity and partly because of its distinctive color.
The Microstructure That Makes Each Type Unique
All dentine-based ivory shares a basic architecture: a collagen matrix mineralized with bioapatite crystals, threaded with microscopic canals called dentinal tubules that radiate outward from the central pulp. These tubules carry nutrients during the tooth’s growth and remain as structural features in the finished material. Their elliptical cross-section measures roughly 3.5 micrometers across.4bioRxiv. Archaeological Ivories: A practical guide for identifying elephant and hippo ivory in the archaeological record At that scale, you cannot see individual tubules with a basic microscope. But the way tubules are arranged and stacked into thin layers creates distinctive patterns visible at low magnification, and those patterns differ from species to species.
In elephant ivory, the tubules create the Schreger line crosshatch. In hippo ivory, they produce the straight parallel bands and helicoidal wave patterns. In walrus ivory, the secondary dentine core has its own recognizable granularity. These species-specific signatures mean that even a small fragment of a centuries-old carved object can be identified to its source animal, which matters enormously for both archaeological scholarship and modern law enforcement. Archaeologists working with ancient ivory artifacts from Mediterranean, African, and Asian sites use exactly these microscopic markers to determine whether a piece was carved from elephant or hippo ivory, information that reveals ancient trade routes and cultural preferences that would otherwise be invisible.
The forensic and archaeological communities have increasingly converged on shared identification protocols. A carved ivory artifact sitting in a museum collection and a suspicious tusk fragment confiscated at a port of entry both require the same underlying analysis. The difference is urgency and legal stakes, but the science is the same: look at the microstructure, match it to a known species pattern, and if the species is protected, determine where and when the animal lived.