sedimentary
Fossilized Bored Limestone
Limestone with Ichnofossils (Gastrochaenolites or Entobia)
Hardness: 3-4 (Mohs); Color: Light grey to beige; Luster: Dull/Earthy; Structure: Carbonate matrix with visible trace fossil borings; Grain: Fine to medium-grained.
- Hardness
- 3-4 (Mohs)
- Color
- Light grey to beige
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-4 (Mohs); Color: Light grey to beige; Luster: Dull/Earthy; Structure: Carbonate matrix with visible trace fossil borings; Grain: Fine to medium-grained.
Formation & geological history
Formed in a shallow marine environment where mollusks or sponges bored holes into hard carbonate substrate. Found in the Fossano region of Italy, which contains Pliocene-age marine sediments from the ancient Po Basin.
Uses & applications
Geological study, local fossil collecting, decoration, and as a natural indicator of paleoenvironmental conditions (shallow warm seas).
Geological facts
The holes are not part of the rock itself but are trace fossils called 'ichnofossils.' They were likely made by bivalves like Lithophaga or sponges. Fossano is famous for its fossil deposits from the Pliocene and Pleistocene epochs.
Field identification & locations
Identify by looking for small, rounded, or teardrop-shaped holes on the surface of river-worn carbonate pebbles. Common along the Stura di Demonte river and associated hiking paths like Sentiero del Pescatore.
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