Judging quality
Stem segments show a five-fold star in cross-section. On plates, judge how much of the crown is exposed and whether the arms are original or sculpted.
Fossil
Crinoid
Sea lilies — stalked echinoderms that carpeted Palaeozoic sea beds. Most material is disarticulated stem segments in limestone; complete crowns with the feeding arms intact are dramatically rarer and prepared over many hours.
Care
Calcite is soft and acid-sensitive. Keep from vinegar, citrus and ultrasonics.
History & lore
In English folklore, crinoid stem discs were 'St Cuthbert's beads' and were strung as rosaries along the Northumbrian coast.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Crinoid
- What is Crinoid?
- Sea lilies — stalked echinoderms that carpeted Palaeozoic sea beds. Most material is disarticulated stem segments in limestone; complete crowns with the feeding arms intact are dramatically rarer and prepared over many hours.
- How hard is Crinoid and what is it made of?
- Crinoid is a Fossil-family mineral with the composition CaCO3 after calcite. It crystallizes in the trigonal system and rates 3-4 on the Mohs hardness scale. It occurs in cream, tan, grey, brown.
- Where does Crinoid come from?
- Notable localities for Crinoid include Indiana, USA, Morocco, England (Derbyshire), China.
- How do you tell good Crinoid from filler?
- Stem segments show a five-fold star in cross-section. On plates, judge how much of the crown is exposed and whether the arms are original or sculpted.
- How do you care for Crinoid?
- Calcite is soft and acid-sensitive. Keep from vinegar, citrus and ultrasonics.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.