sedimentary

Goniatite Fossil

Goniatitida (Order), fossilized in limestone/calcite (CaCO3)

Hardness: 3-4 (Mohs scale); Color: Black, grey, and white; Luster: Polished/Waxy; Structure: Planispiral coiled shell with zig-zag (goniatitic) suture lines; Cleavage: None (conchoidal fracture on matrix).

Hardness: 3-4 (Mohs scale)
Color: Black, grey, and white
Luster: Polished/Waxy

Identified March 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through permineralization of extinct cephalopod shells in marine environments. These specimens typically date to the Devonian period (approx. 360-400 million years ago), commonly found in the Anti-Atlas Mountains of Morocco.

Uses & applications

Primarily used as decorative display pieces, for geological education, in jewelry making (pendants), and as a common entry-grade specimen for fossil collectors.

Geological facts

Goniatites are ancestors of the more famous Ammonites. They are distinguished by their suture lines—the complex patterns where the internal chamber walls (septa) meet the outer shell. In Goniatites, these lines are relatively simple zig-zags compared to the fractal-like patterns of later ammonites.

Field identification & locations

Identify in the field by looking for the distinct 'chambered' spiral shape embedded in dark limestone. Most commercial specimens are mined in Morocco, polished to reveal the contrast between the white calcite-filled chambers and the dark rock matrix.

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