Glossary · Preservation
Concretion
A hard, rounded mass that grew in sediment by precipitation of a cementing mineral (calcite, siderite, phosphate) around a nucleus, often a fossil; the Mazon Creek siderite nodules and the Santana phosphate concretions are the classic fossil concretions.
A hard, rounded mass that grew in sediment by precipitation of a cementing mineral (calcite, siderite, phosphate) around a nucleus, often a fossil; the Mazon Creek siderite nodules and the Santana phosphate concretions are the classic fossil concretions.
Sources
Cite this article
Stratum Study. "Concretion" (Glossary). Stratum Study pack 2026.09, as of 2026-09-16. https://stratum.black/study/glossary/concretion. Accessed 2026-09-20.
@misc{stratum-concretion,
title = {Concretion},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/glossary/concretion}},
year = {2026},
note = {Glossary article, Stratum Study pack 2026.09, as of 2026-09-16; sources: stratum. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.