A very interesting rock from the sophisticated collector is the “Mary Ellen Jasper “. It is named after its occurrence in the Mary Ellen mine. This mine is situated in the iron ore occurrences of  the Mesabi Range, St Louis County, Minnesota. „The Mary Ellen Jasper “is a witness of the emergence of the life on earth. In its silificied structures very old blue algae are conserved.

It is not only a coincidence that these fossils are in close proximity to oxidic iron ores - they are the cause for it. This forms of primitive life - beginning in the precambric era (in this case 2.4 billion years ago) produced the first free oxygen that enricheds in the atmosphere. The so far free and natively  iron was confronted with the radical oxygen - it oxidized, it rusted. The iron settled in layers, which form the today's striped iron ores. Rarely collectores could find non oxidized “Mary Ellen Jaspers” - they remained greenish.

The structures of fossil blue algae, conserved in „the Mary inches Jaspis the “, are called Stromatolithes. The blue algae Collenia undosa formed fine algae foams, which got stuck at prominent place and represent so wavelike patterns in the received jasper.

the website www.northshore-rocks.com is offering more information to this topic.