Bone vs Ivory
Bone and Ivory are commonly confused, and 1 measured property separates them — density most clearly.
Bone vs Ivory
Bone
Mineral crystals grown on a protein scaffold — stiff like a ceramic and tough like a polymer, which no engineered material manages at once.
Ivory
Tooth dentine, carveable in any direction and taking a polish like nothing else — the most legally restricted material there is, and for good reason.
| Property | Bone | Ivory |
|---|---|---|
| Density | 1.8–2.1 g/cm³ higher | 1.7–1.98 g/cm³ |
| Mohs hardness Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 2–3 |
| Tensile strength Only one of the two has a figure we can stand behind, so there is nothing to compare. | 100–150 MPa | Not known |
| Young's modulus Only one of the two has a figure we can stand behind, so there is nothing to compare. | 15–25 GPa | Not known |
Why these get confused
the confusion that matters legally, and one a hand lens settles: bone shows Haversian canals as dark pits and streaks, ivory shows none, and elephant and mammoth ivory show Schreger lines that nothing else does
The confusion is a real and documented one, not a resemblance we have invented.