sedimentary
Crinaudite / Fossilized Crinoid Stem
Crinoid (Echinodermata) in a Calcitic/Siliceous Matrix
Hardness: 3 (if calcite) to 7 (if silicified/jasperized). Color: Dark gray/black matrix with white or light gray circular fossils. Luster: Dull to waxy. Structure: Distinct circular, radial, or star-shaped star patterns representing cross-sections of crinoid columnals.
- Hardness
- 3 (if calcite) to 7 (if silicified/jasperized)
- Luster
- Dull to waxy
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Physical properties
Hardness: 3 (if calcite) to 7 (if silicified/jasperized). Color: Dark gray/black matrix with white or light gray circular fossils. Luster: Dull to waxy. Structure: Distinct circular, radial, or star-shaped star patterns representing cross-sections of crinoid columnals.
Formation & geological history
Formed in marine environments from the skeletal remains of crinoids (sea lilies). These echinoderms lived in vast 'gardens' during the Paleozoic era (approx. 250-500 million years ago) and their calcium carbonate stems accumulated in seafloor sediment.
Uses & applications
Used primarily for jewelry (cabochons), river stones, ornamental decor, and as educational fossils for geological study/collecting.
Geological facts
Crinoids are animals, not plants, despite their 'lily' nickname. When their segmented stems are found in rock, they are often called 'fairy stones' or 'St. Cuthbert’s beads' in folklore.
Field identification & locations
Identify in the field by looking for the 'Cherriot wheel' or 'donut' shapes within dark limestone or shale. Commonly found in areas with exposed Paleozoic limestone, such as the Midwestern USA, the UK (Derbyshire), and Russia.
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