fossil

Fossilized Coral

Scleractinia (Agatized or Calcite replaced)

Hardness: 3-4 (calcite) or 6.5-7 (agatized); Color: Cream, white, or light tan; Luster: Dull to waxy; Texture: Ornate skeletal structures with septa and pores; Composition: CaCO3 or SiO2-replacement.

Hardness: 3-4 (calcite) or 6
Color: Cream, white, or light tan
Luster: Dull to waxy

Identified July 10, 2026More fossil →

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Physical properties

Hardness: 3-4 (calcite) or 6.5-7 (agatized); Color: Cream, white, or light tan; Luster: Dull to waxy; Texture: Ornate skeletal structures with septa and pores; Composition: CaCO3 or SiO2-replacement.

Formation & geological history

Formed in ancient warm, shallow marine environments where coral polyps built calcium carbonate skeletons. Over millions of years, these were buried and replaced by minerals like calcite or chalcedony.

Uses & applications

Used for home decor, aquarium landscaping, lapidary work (when agatized), and as educational geological specimens.

Geological facts

Coral fossils serve as 'paleothermometers' helping scientists determine ancient sea temperatures and marine health throughout different geological periods.

Field identification & locations

Identify by the repetitive geometric patterns of the coral polyps. Found along coastal regions, ancient sea beds, and limestone quarries globally, particularly in Florida, Michigan (Petoskey stones), and Indonesia.

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