sedimentary

Crinoid Fossil Marble

Crinoidal Limestone / Phylum Echinodermata

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs scale); Color: Dark grey or black matrix with white or cream fossils; Luster: Dull to earthy; Structure: Biogenic fragments in a fine-grained matrix; Cleavage: None (conchoidal fracture in matrix).

Hardness: 3-4 (Mohs scale)
Color: Dark grey or black matrix with white or cream fossils
Luster: Dull to earthy

Identified May 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of skeletal remains from crinoids (sea lilies) on the ocean floor during the Paleozoic era (approx. 300-500 million years ago), which were then lithified into limestone.

Uses & applications

Primarily used for educational collecting, decorative stone, lapidary work (polishing into pebbles), and occasionally in architectural tiling or fireplace surrounds.

Geological facts

Crinoids are actually animals (echinoderms) related to starfish and sea urchins, not plants, despite their 'sea lily' nickname. The circular patterns in this specimen are cross-sections of the animal's stem.

Field identification & locations

Identifiable by the distinct 'cheerio' or star-shaped white circles embedded in a darker rock. Commonly found in limestone-rich regions like the UK (Derbyshire), the Midwestern US, and Morocco.