Stromatolite Tumbled 1 pc

1 pc. Approx 0.75-1" Stromatolite is the name given to a rock formation that is composed of the fossilized remains of a micro organism know as cyanobacteria, which is also called blue green algae, (although not strictly an algae). Stromatolites are characterized by layers of banding or swirls caused by the trapping, binding and cementation of sedimentary grains by the micro organisms. It is a combination of Jasper, silicon dioxide with various impurities and iron oxides, and the colors and markings can range from a brown/tan with dark brown/black markings to green/blue with blue toned markings.