Viewing this specimen it is easy to see why jewelry makers prize this Lower Proterozoic stromatolite from the Mary Ellen Mine in Minnesota, that is commonly known as Mary Ellen Jasper. As in this piece, the colors displayed can be truly stunning.

Scientifically known as Collenia undosa, the microorganism-makers were likely to have been photosynthetic bacteria that were busily consuming sunlight and water to live and clone themselves, and expiring oxygen that would ultimately constitute the modern atmosphere on earth. Note the multiplicity of vivid colors and the embedded quartz cyrstals. Much beauty and much science in the same piece of rock.

Remarkably, the specimen contains several Girvanella forms that is extremely rarely seen in the stromatolite from this locality.