Stratum.black

Glossary · Preservation

Mould and cast

A mould is the impression left in sediment by an organism after it dissolves; a cast is sediment or mineral that later fills the mould and reproduces the original shape.

A mould is the impression left in sediment by an organism after it dissolves; a cast is sediment or mineral that later fills the mould and reproduces the original shape. External and internal moulds (steinkerns) are the usual state of many molluscs in sandstone.

Sources

Cite this article

Stratum Study. "Mould and cast" (Glossary). Stratum Study pack 2026.09, as of 2026-09-16. https://stratum.black/study/glossary/mold-and-cast. Accessed 2026-09-20.

BibTeX · CSL-JSON

@misc{stratum-mold-and-cast,
  title        = {Mould and cast},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/glossary/mold-and-cast}},
  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.

Sources for this article: Stratum editorial (Stratum editorial). As of 2026-09-16; Study pack 2026.09. Written by Stratum in our own words; the works cited are where the science lives, and none of their text is reproduced here.

Found an error? Write to drew@tyr.ac with the article id glossary:mold-and-cast.