A spectacular and highly decorative Kona Dolomite stromatolite, from the Kona Hills area near Marquette, Michigan, USA. This large natural specimen displays beautifully preserved, undulating stromatolitic laminations in shades of red, pink, cream, grey and brown, with contrasting dark mineral-rich areas. The polished surfaces reveal the complex internal architecture created by ancient microbial communities. Geological Information Material: Kona Dolomite – stromatolitic dolomite Fossil: Stromatolite Age: approximately 2.2 billion years Geological era: Paleoproterozoic Locality: Kona Hills, Marquette County, Michigan, USA Weight: approximately 1,3 kg Dimensions: approximately 16 x 13 x 4 cm This stromatolite formed in a shallow marine environment more than two billion years ago, when microbial mats were among the dominant forms of life on Earth. The age of the Kona Dolomite is particularly significant because it falls within the broad interval associated with the Great Oxidation Event, one of the most important transitions in Earth's history. During this period, oxygen produced by photosynthetic microorganisms began to accumulate in Earth's atmosphere, profoundly changing the chemistry of the oceans and atmosphere and eventually enabling the evolution of more complex life. A remarkable piece of Earth's deep biological and geological history, combining exceptional visual appeal with genuine Paleoproterozoic scientific significance. The specimen shown in the photographs is the exact specimen offered for sale. Photo taken under a LED Note: To emphasize the color it is necessary to expose it under an LED light. To the naked eye with only indirect light the effect is not the same as in the photos.