Stromatolite or maybe not?

Having collected stromatolites in several locations in New York and Ontario, I was attracted to a small polished piece offered this past October by a dealer at the Rochester Gem and Mineral show.  It was labeled Kabamba Jasper – stromatolite, Madagascar.   It was a pretty green color, showed physical characteristics of a stromatolitic origin, and best of all, it was reasonably priced.  I bought it and came home to research the geology and age of my new find.   Immediately, things got complicated.

My polished piece of Kabamba Jasper – Madagascar: But is it really of biologic origin?

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