How to identify Fossilized Tooth Fragment

To correctly identify Fossilized Tooth Fragment (Fossilized biological material (likely dentin/enamel)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Highly variable, often shades of brown, black, gray, tan, or reddish, depending on the mineral composition of the surrounding sediment and the fossilization process. Some can be white or cream if permineralized with light-colored minerals.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Dull to sub-vitreous, sometimes waxy or earthy. Enamel can retain a slightly vitreous luster if well-preserved.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to slightly granular, often exhibiting the original surface features of the tooth, such as cusps, ridges, and root morphology. Can feel dense and hard.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Not applicable in the traditional sense for a mineral. The original biological structure is preserved, but the constituent minerals (e.g., apatite, calcite, quartz) may be microcrystalline or cryptocrystalline.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None in the macroscopic sense. Fracture is typically conchoidal to irregular, reflecting the original biological structure and subsequent diagenesis.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in sedimentary environments where rapid burial and mineral-rich groundwater facilitate fossilization. Common in marine sediments (e.g., shark teeth in ancient seafloors), fluvial deposits (riverbeds), lacustrine deposits (lakebeds), and terrestrial sedimentary rocks (e.g., badlands, ancient floodplains).

Key Facts

Hardness

Variable, typically 5-7 on the Mohs scale, depending on the degree of mineralization and the specific minerals involved. Original enamel is ~5, but fossilization can increase or decrease this.

Specific Gravity

Variable, typically 2.5-3.2, depending on the degree of mineralization and the specific minerals involved. Original enamel is ~2.9-3.0.

Crystal System

Not applicable for the overall fossil. The primary mineral component, hydroxyapatite, is hexagonal. Secondary minerals can be various systems.

Color

Highly variable: brown, black, gray, tan, reddish, white, cream.

Luster

Dull to sub-vitreous, waxy, earthy.

Transparency

Opaque.

Fracture

Conchoidal to irregular, reflecting the original biological structure and diagenesis.

Cleavage

None.

Composition

Primarily calcium phosphate (hydroxyapatite, Ca5(PO4)3(OH,F,Cl)) that has been permineralized or replaced by other minerals such as calcite (CaCO3), silica (SiO2), pyrite (FeS2), or iron oxides. Trace elements from the original organism and the burial environment may also be present.

Physical characteristics

• Crystal Habit: Not applicable for the overall fossil. Microcrystalline or cryptocrystalline aggregates of constituent minerals.
• Cleavage Type: None.
• Fracture Type: Conchoidal to irregular.
• Tenacity: Brittle.
• Luster Type: Dull, sub-vitreous, waxy, earthy.

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