These curious stones are native to Michigan, and stand out for the hexagonal “scales” that cover their surface. What are they exactly? And why do they have this shape?
The petoskey stones they are so named because they are only found in Michigan near the town of Petoskey. They are characterized by the layer of hexagonal “scales” that run along its surface. They are highly valued for their beauty. But what are they?
The name of petoskey stones It is a tribute to an Ottawa chief, Chief Pet-O-Sega, the son of a French fur trader and an Ottawa mother.
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Petosegay made a lot of money as a fur trader, buying large pieces of land where he began building houses to form a settlement, in 1873. They called it Petoskey, an English adaptation of its original name.
What are Petoskey stones?
Petoskey stones are only found on the Michigan peninsula. Its peculiar design, with those hexagonal “scales”, is actually due to the fact that These are fossilized corals from 350 million years ago..
These stones formed as a result of glaciation, in which ice sheets ripped up bedrock stones made up of fossilized corals, crushed their rough edges, and deposited them in the northwestern part of Michigan’s lower peninsula.
There you can find both fossilized corals and already rounded Petoskey stones:

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Unpolished stones do not show fossilized coral, so they are often polished to show the mottled layer.
The best place to find them is on the shores of Lake Michigan.. But they can also be found in dry areas, hills, and other places. It has become the official state stone of Michigan.
Are fossil stones they can be collected freely, although there are a number of rules. Each citizen can collect a maximum of 11 kilos of fossils per year, and to sell them you need a permit.
Therefore, we already know that Petoskey stones are actually fossilized corals from 350 million years ago. In Spain they are not easy to find, but on eBay they are for sale with shipping from the United States, and prices between 40 and 80 euros.