Crinoid Stem Segments (Columnals)
Indeterminate crinoid species (cf. Platycrinites sp.) • Body fossil; Invertebrate (Echinoderm)
Geological Period
Carboniferous Period (Mississippian to Pennsylvanian)
Estimated Age
300 to 360 million years
Preservation Type
Recrystallization; often replaced by calcite or silica. The original calcium carbonate structure has been mineralized.
Condition Assessment
Good. The specimens are weathered and detached (disarticulated), which is common. They show signs of abrasion but maintain clear diagnostic central lumens and lobed shapes.
Taxonomic Classification
Phylum: Echinodermata; Class: Crinoidea; Order: Millericrinida (or similar fossil orders); Family: Various; Genus: cf. Platycrinites or Encrinus
Morphological Description
Pentagonal to circular discoidal segments known as columnals. Features include a central hollow canal (lumen) and distinct radial symmetry or lobed appearance. These segments are vertically stacked in life to form the stalk or stem of the 'sea lily'.
Rock Matrix
Isolated specimens removed from matrix; likely derived from a limestone or calcareous shale environment. Common associated minerals include calcite and quartz.
Formation & Location
Commonly found in the Burlington Limestone (USA), Crawfordsville (Indiana), or Northern England (UK Carboniferous layers).
Size & Dimensions
Approximately 1cm to 2cm in diameter. These are typical, standard-sized columnals for common Paleozoic crinoids.
Value & Rarity
Estimated Market Value
$2 - $10 USD per segment
Auction Estimate
$20 - $50 USD for a small bulk lot (unframed)
Rarity Assessment
Common. Crinoid stem fragments are among the most abundant macrofossils found in Carboniferous limestone deposits globally.
Scientific Significance
Crinoids are vital index fossils for dating Paleozoic strata. They provide information on high-energy, shallow marine environments and the evolution of suspension feeders in ancient oceans.
Preparation Recommendations
No intensive preparation needed. Can be cleaned with water and a soft brush. Store in a dry environment; often used for jewelry (as seen by the bracelet in the background).
Notable Features
Often referred to as 'St. Cuthbert’s beads' or 'fairy coins' in folklore. The specimens displayed here have been naturally or manually drilled/cleaned for use as beads, emphasizing their historical use in jewelry.