Petoskey Stone

from Michigan, USA

What is a Petoskey Stone?

The Petoskey stone is a silicified coral from the Devonian period about ~420 to 360 million years ago. During that period, Michigan was a tropical reef located near the equator. More recently, the glaciers plucked and deposited the now fossilized coral around the NW coast of Michigan’s lower peninsula near the town of Petoskey. The popular Michigan state stones are sought after by many beach combers. 

Under the Microscope

The organic structure of this once living colony coral is still present even though quartz has replaced the original mineral, aragonite or calcite. Each circular flower design was a separate chamber that functioned as a mouth for the colony. 

Unlike our other designs so far, our thin section is actually a “thick” section being 100 microns thick instead of the normal 30 microns. So what does that mean? The colors of quartz in cross-polarized light are more colorful than the usual greys we expect from a standard thin section. 

Blog Coming Soon…

Coral Dawn

Transmitted, Cross-Polarized Light

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