Stromatolite

About it

Layered domes and columns built by mats of cyanobacteria trapping sediment, seen as wavy bands when cut. Among the oldest fossils, over 3 billion years; Minnesota's Mary Ellen jasper is one, and living ones grow in Shark Bay, Australia.

Type

Fossil (other)

Group

Stromatolite (microbial)

Colours

grey, brown, tan, red, black, banded

Transparency

opaque

Periods

Precambrian, Cambrian, Ordovician

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