Key properties
| Chemical formula | Ca5(PO4)3(OH) (hydroxyapatite) with collagen; roughly 60-70% mineral in a protein matrix |
| Crystal system | None (biological composite, non-crystalline) |
| Mohs hardness | 2.5 |
| Toughness | Fair |
| Refractive index | 1.540-1.550 |
| Optic character | Aggregate (AGG) |
| Specific gravity | 1.90-2.20 |
| Cleavage | None |
| Fracture | Uneven to splintery |
| Habit | Not applicable; worked skeletal sections, beads and carving blocks |
| Lustre | Dull to greasy; polish: Waxy to greasy |
| UV fluorescence | Not diagnostic; commonly weak bluish white under long-wave UV (the mineral fraction may fluoresce) |
| Pleochroism | None |
| Cause of colour | Natural bone is whitish from hydroxyapatite and residual collagen; cream to brown tones come from ageing, soil/oil staining and heating; strong colours are always dye |
| Typical inclusions | Diagnostic structure: Haversian canals and blood-vessel channels appear as round or oval dark dots and short lines; surface looks pitted or porous where channels are exposed; no Schreger cross-hatching |
| Stability | Fair to poor; the organic fraction degrades with age. Attacked by acids and strong chemicals; burns with a protein (burnt hair) odour |
| Heat sensitivity | High; scorches, shrinks and cracks with heat |
| Care and cleaning | Warm soapy water with a soft brush only; never ultrasonic or steam. Bone is porous, so avoid prolonged soaking and dry slowly away from radiators |
| Birthstones | None |
| Availability | Widely available and inexpensive; cattle, camel and buffalo bone are the usual sources. No trade restrictions on common domestic species |
| Recognition | Best known in ethnic and tribal jewellery, prayer beads, bangles, buttons and carvings; engraved scrimshaw on whale bone or tooth is a collector field |
Varieties
Bone
| Colour | opaque white to cream and yellowish brown; dyed bone can be almost any colour |
| Transparency | opaque |
| Clarity type | Opaque, always with visible canal structure |
| Phenomena | None |
| Appearance | Smooth, waxy-looking white to cream material, often with grey-brown age staining; magnification shows the dotted, porous canal network of living bone |
| Trade names | camel bone • beef/cattle bone • buffalo bone • scrimshaw (engraved antique work) • fossil or mineralised bone |
| Misnomers | dyed bone sold as coral or turquoise in ethnic jewellery • carved bone marketed as 'genuine ivory' • odontolite ('bone turquoise') is fossil bone or ivory stained blue-green by vivianite, not turquoise |
| Typical sizes | Beads from about 4 to 20 mm; bangles and carving blocks up to roughly 15-20 cm from large leg bones |
| Cutting styles | Beads, cabochons, bangles, carved figures and pendants, buttons, inlay; antique scrimshaw is engraved and inked |
| Key separations | vs ivory: ivory shows Schreger cross-hatching, bone shows scattered round/oval dark canals. vs vegetable ivory: tagua is granular with no canal holes and floats lower (SG about 1.40 vs about 2.0). vs plastic: plastic is smooth to the tooth, lower SG (about 1.3), melts with a hot point and gives no canal structure. vs horn: horn is fibrous with an undulating layered look and SG nearer 1.7-1.85 |
| Sources (localities) | Worldwide; mostly slaughterhouse by-product of domestic cattle, buffalo and camel • India and Indonesia supply carved bone beads and bangles • China and Nepal export carved pendants • fossil bone (including dyed 'turquoise bone') from older deposits |
| Availability | Plentiful and cheap in ethnic-jewellery channels; quality carving requires dense, well-dried bone |
| Market notes | Sold openly and sustainably; watch for bone dyed to imitate coral or turquoise and for 'antique ivory' claims on stained bone. Some countries restrict export of bone from protected species (e.g. whale) |
| Care notes | Last on, first off: keep away from perfumes, solvents and prolonged water. Store away from heat and sunlight; re-oil occasionally if the piece dries out |
| In short | Carved domestic bone is the commonest and cheapest of the white organic gem materials, easily recognised by its dotted canal structure under magnification. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–5.00 | $0.05 – $0.50 | bulk beads and components | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Sources
Data compiled and fact-checked against gemmological literature, October 2026 (JDMIS gem reference). Properties are ranges accepted in gemmological practice; individual stones vary.
See also
Gemstone reference entries: gem #137 · gem #183
Related materials: Corundum · Diamond · Opal · Quartz · Spinel · Topaz
Identification wizard · All 83 materials · Singapore gem labs