|  This
stromatolite is at once, ancient (Precambrian), beautiful, and
unusually colored. The unsual, rare and asthetic characteristic
is a significant content of Rhodochrosite. Rhodochrosite (MnCO3,
Manganese Carbonate - whose name means rose-colored) is a very
attractive mineral with an absolutely one-of-a-kind, beautiful
color that is a gemstone in crystal form, and otherwise used in
various jewelry applications. The Rhodochrosite here is the red
blotches in the upper half. Although it can be an ore of manganese,
it is its ornamental and display specimen qualities that make
it a very popular mineral. The color of a single crystal can just
astound the observer with its vivid pink-rose color that seems
to be transmitted out of the crystal as if lit from within.
Coming
from the Chocolay Group in an area known as the Chocolay Hills
located southeast of Ishpeming, Michigan, this stromatolite dates
to the Lower Proterozoic, some 2.2 to 2.4 Billion years old. The
specimen that has been hand-polished to a mirror finish on one
side exhibits intricate banding prototypical in stromatolites.
The fossil is the evidence of the great oxigenation event that
ranks among the most important phenomena that drove evolution
of life on Earth.
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