This specimen grew on the ancient continent of Nena in a saltwater swamp at a time when years were well over 400 days long, the earliest members of the plant family were only just appearing, and this very creature was losing its ecological niche as an increasingly oxygen-rich atmosphere paved the way for competition.

Often overlooked by fossil collectors and yet one of the most fascinating of fossils. Stromatolite, Greek for "stony carpet", is the remnant of an ancient colony of microorganisms. They were the only life on earth for some 2 billion years, give or take a couple hundred million, and they (i.e., bacteria) remain today the largest portion of the biomass of planet earth.

This specimen has been sliced horizontally though the colony. The exotic-looking pattern of concentric shapes on this piece are actually cross-sections of its upward reaching branches. This branching structure suggests that Yelma Digitata is a more highly evolved stromatolite, older forms being more laminar, though whether it is of prokaryotic and eukaryotic origin would be a matter of conjecture.

This gorgeous, thick piece, with its creamy coral-pinks, taupes, and black on yellow "leopard print" patterns is the perfect size for office or museum display. Picked up at the Tucson Gem & Mineral show from Austrailian traders, this species of stromatolite is not easy to come by in the states, and its weight makes shipping from Australia expensive.

The specimen is beautifully polished on the onverse and rough on the reverse, and weighs a whopping 7.6 pounds.