Distinguishing ivory from bone can be challenging, especially for untrained eyes. Both materials have been used for centuries in art, jewelry, and utilitarian objects. However, knowing the differences is crucial for ethical sourcing, accurate identification of antiques, and complying with wildlife protection laws. This comprehensive guide provides detailed steps and instructions to help you tell ivory from bone with confidence.
Why is it Important to Distinguish Ivory from Bone?
There are several compelling reasons why it’s essential to distinguish ivory from bone:
- Ethical Concerns: Ivory trade is often linked to poaching and the illegal killing of elephants, walruses, and other animals. By correctly identifying materials, you can avoid supporting unethical practices and contribute to wildlife conservation.
- Legal Compliance: Many countries have strict regulations regarding the trade and possession of ivory. Misidentification can lead to legal complications, including fines and confiscation of items.
- Accurate Appraisal: The value of an object depends heavily on the material it’s made from. Ivory is generally more valuable than bone, so accurate identification is critical for appraisals, insurance, and resale.
- Conservation and Preservation: Understanding the material composition helps in choosing the appropriate conservation and preservation methods, ensuring the longevity of valuable artifacts.
Understanding the Composition of Ivory and Bone
Before diving into the identification methods, it’s helpful to understand the basic composition of ivory and bone:
- Ivory: Primarily composed of dentine, a dense, compact material. It’s derived from the teeth and tusks of various animals, including elephants, walruses, hippos, and narwhals. The most common type of ivory encountered is elephant ivory.
- Bone: Composed of collagen, a protein matrix, and calcium phosphate. Bone is a porous material with a more complex structure than ivory. It’s sourced from the skeletons of animals, including cows, horses, and other livestock.
Key Differences Between Ivory and Bone
Here’s a summary of the key characteristics that differentiate ivory from bone:
- Schreger Lines: Unique to elephant ivory, these are cross-hatched patterns visible on the end grain.
- Haversian Systems: Present in bone, these are tiny canals that appear as small dots or circles under magnification. Ivory lacks Haversian systems.
- Grain Structure: Ivory has a smoother, more homogenous grain structure compared to bone, which is more porous and textured.
- Color: Ivory typically has a creamy white or yellowish hue. Bone can range from white to grayish-brown.
- Density and Weight: Ivory is generally denser and heavier than bone.
- Luster: Ivory often has a subtle, waxy luster, while bone tends to be more matte.
Detailed Steps to Tell Ivory from Bone
Now, let’s explore the detailed steps you can take to distinguish ivory from bone:
1. Visual Inspection
Start with a thorough visual examination of the object. Use a magnifying glass or jeweler’s loupe to observe the surface details.
- Check for Schreger Lines: Look at the end grain of the object. If it’s elephant ivory, you should see Schreger lines, which appear as a cross-hatched or engine-turned pattern. The angle of the Schreger lines is also important. Elephant ivory typically has angles greater than 115 degrees, while mammoth ivory has angles less than 90 degrees. Note that this test only applies to elephant and mammoth ivory; other types of ivory will not exhibit Schreger lines.
- Look for Haversian Systems: Examine the surface closely for tiny dots or circles. These are Haversian systems, which are characteristic of bone. If you see them, it’s likely bone, not ivory.
- Assess the Grain Structure: Observe the overall grain pattern. Ivory typically has a smoother, more consistent grain than bone. Bone tends to have a more porous and textured appearance.
- Evaluate the Color: Note the color of the material. Ivory often has a creamy white or yellowish hue. Bone can range from white to grayish-brown. However, color alone is not a reliable indicator, as both materials can be stained or dyed.
2. Magnification
Use a magnifying glass, jeweler’s loupe, or microscope to examine the surface features in greater detail. Magnification is essential for identifying Haversian systems and assessing the grain structure.
- Examine for Haversian Systems: Under magnification, Haversian systems appear as small, dark dots or circles scattered throughout the material. Their presence strongly suggests that the object is made of bone.
- Assess the Pore Structure: Magnification allows you to examine the pore structure of the material. Bone typically has more visible pores and a rougher surface texture compared to ivory.
3. The Pin Test (Use with Caution!)
Important Note: This test should be performed with extreme caution and only on an inconspicuous area of the object, as it can cause damage. The pin test involves gently inserting a hot needle into the material to observe its reaction. This test is generally not recommended for valuable or antique items.
- Heat a Needle: Heat a needle with a lighter or flame until it is hot.
- Gently Insert: Gently touch the hot needle to an inconspicuous area of the object.
- Observe the Reaction: If the material is bone, it will often emit a smell similar to burning hair. Ivory is more resistant to heat and may not emit a strong odor.
- Examine the Surface: After the test, examine the area where the needle was applied. Bone is more likely to melt or leave a visible mark compared to ivory.
Disclaimer: The pin test is not foolproof and can damage the object. It should be used as a last resort and only by experienced individuals.
4. The Hot Needle Test (Not Recommended)
This test is extremely destructive and should NEVER be performed on valuable or antique items. It involves inserting a heated needle into the material to observe the reaction and smell. This test can cause irreversible damage and is generally not recommended.
5. The Density Test
Ivory is generally denser than bone. Although this is not a definitive test and requires that you know the volume of the item, it can provide a clue. If you can accurately measure the volume of the object (e.g., by water displacement) and weigh it, you can calculate its density. Ivory typically has a density of around 1.7 to 2.0 g/cm³, while bone has a density of around 1.7 to 2.0 g/cm³.
6. The UV Light Test
Under ultraviolet (UV) light, ivory and bone may exhibit different fluorescence patterns. However, this test is not always reliable, as the fluorescence can be affected by age, treatment, and other factors. Additionally, some plastics can mimic the fluorescence of ivory, so this test should be used in conjunction with other identification methods.
- Ivory: Typically fluoresces with a bright white or bluish-white color under UV light.
- Bone: May fluoresce with a duller white or yellowish color.
7. Microscopic Analysis
For a definitive identification, microscopic analysis is the most reliable method. This involves taking a small sample of the material and examining it under a high-powered microscope.
- Identification of Structures: Microscopic analysis allows for the clear identification of Schreger lines, Haversian systems, and other characteristic structures of ivory and bone.
- Expert Interpretation: Microscopic analysis requires specialized equipment and expertise. It’s best performed by a trained conservator or materials scientist.
8. Chemical Testing (Requires Expertise)
Chemical testing involves analyzing the chemical composition of the material to identify the presence of specific elements or compounds. This method is generally used in laboratory settings and requires specialized equipment and expertise.
- Raman Spectroscopy: This technique can identify the molecular composition of the material, distinguishing between the organic and inorganic components of ivory and bone.
- X-ray Diffraction: This method can determine the crystalline structure of the material, providing information about its mineral content.
Common Materials Confused with Ivory and Bone
It’s important to be aware of other materials that can be easily confused with ivory and bone. These include:
- Plastic: Modern plastics can closely mimic the appearance of ivory and bone. Look for mold marks, seams, or a lack of natural grain patterns.
- Vegetable Ivory (Tagua Nut): This material is derived from the seeds of certain palm trees and has a similar appearance to ivory. However, vegetable ivory lacks Schreger lines and has a different grain structure.
- Horn: Horn is composed of keratin and has a different structure than ivory and bone. It often has a layered or fibrous appearance.
- Antler: Antler is bone-like material that grows on the heads of deer and other animals. It has a porous structure and may be difficult to distinguish from bone.
- Resin: Resin-based materials can be cast to resemble ivory or bone. They often lack the density and weight of natural materials.
Tips for Handling and Caring for Ivory and Bone Objects
Proper handling and care are essential for preserving ivory and bone objects:
- Avoid Extreme Temperatures and Humidity: Ivory and bone are sensitive to changes in temperature and humidity. Store objects in a stable environment to prevent cracking or warping.
- Handle with Clean Hands: Oils and dirt from your hands can damage the surface of ivory and bone. Always handle objects with clean hands or wear gloves.
- Dust Regularly: Use a soft brush or cloth to remove dust from the surface of the object.
- Avoid Harsh Cleaners: Do not use harsh chemicals or abrasive cleaners on ivory or bone. These can damage the surface and alter the color.
- Seek Professional Conservation: For valuable or antique objects, consult a professional conservator for cleaning and repair.
Ethical Considerations and Legal Regulations
It’s crucial to be aware of the ethical considerations and legal regulations surrounding ivory trade. Many countries have banned the import, export, and sale of ivory to protect endangered species.
- CITES Regulations: The Convention on International Trade in Endangered Species (CITES) regulates the international trade of ivory. Check the CITES regulations in your country before buying or selling ivory objects.
- National Laws: Many countries have their own laws regarding ivory trade. Be aware of the specific regulations in your jurisdiction.
- Support Sustainable Alternatives: Consider supporting sustainable alternatives to ivory, such as vegetable ivory or ethically sourced bone.
Conclusion
Distinguishing ivory from bone requires a combination of careful observation, magnification, and, in some cases, specialized testing. By following the detailed steps and instructions in this guide, you can improve your ability to identify these materials accurately. Remember to prioritize ethical considerations and legal compliance when dealing with ivory objects. If you’re unsure about the identification of an object, it’s always best to consult with a professional conservator or appraiser.
Disclaimer
This guide provides general information for educational purposes only. It should not be considered a substitute for professional advice. The identification of ivory and bone can be complex, and the accuracy of any identification method depends on the skill and experience of the observer. Always exercise caution and seek expert advice when dealing with valuable or antique objects.
Additional Resources
- The Convention on International Trade in Endangered Species (CITES): https://www.cites.org/
- International Ivory Society: https://ivorysociety.org/
- Local museums and conservation organizations