fossil
Rugose Coral Fossil
Order Rugosa
Hardness: 3-4 (calcite), Color: Brown to tan, Luster: Dull or earthy, Crystal Structure: Trigonal (calcium carbonate), Specific Gravity: 2.7
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Physical properties
Hardness: 3-4 (calcite), Color: Brown to tan, Luster: Dull or earthy, Crystal Structure: Trigonal (calcium carbonate), Specific Gravity: 2.7
Formation & geological history
Formed through permineralization or replacement of ancient marine organism skeletons in shallow Paleozoic seas, approximately 250 to 500 million years ago.
Uses & applications
Used primarily as educational specimens, in fossil collecting, and occasionally crafted into decorative cabochons or jewelry.
Geological facts
Rugose corals are commonly known as 'horn corals' due to their distinctive horn-like shape. They went extinct during the Permian-Triassic extinction event.
Field identification & locations
Easily identified by their conical shape and prominent radial septa visible on the coral cup or cross-section. Commonly found in limestone deposits worldwide.
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