Calamites

About it

Stems of tree-sized horsetails, usually found as casts with lengthwise ribs interrupted at regular joints. Abundant in Carboniferous coal-measure rocks of Europe and North America; living horsetails are small relatives.

Type

Fossil (plant)

Group

Horsetail (plant)

Colours

grey, black, brown

Transparency

opaque

Periods

Carboniferous, Permian

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