A stromatolite is a solid structure created by single-celled microbes called cyanobacteria. The cyanobacteria forms colonies, and in turn, traps sediment with its' sticky surface coatings.
The remaining formations are quite stunning.
1200-1300 million years old. Torgo, Saka-Jakuita, Russia.
Approximately 5.5" long, 3.5" at the widest point.
*Display stand not included, but you can purchase one here: