Orthoceras

Fossil

Also called Orthocone and Orthocerid

About it

Straight, cone-shaped nautiloid shells with a central siphuncle, best known polished in black limestone from Morocco. Those are Devonian orthocerids sold under the name; true Orthoceras is Ordovician, from Sweden and the Baltic.

Type
Fossil (mollusc)
Group
Cephalopod (mollusc)
Colours
black, grey, brown, cream
Transparency
opaque
Periods
Ordovician, Silurian, Devonian

Typical values: real specimens vary. For more, see mindat.org.