Handfuls of Manitoulin Island

While on Manitoulin Island -- the largest island in the Great Lakes basin -- I found many fascinating fossils and stones:

Crinoid and quartz

This last one is a fossilized sponge

Manitoulin Island is the largest island in the 

Great Lakes. This is one of the many islands I explored for my upcoming book.

The World's Largest Celestite Geode

I've taken a hammer to quite a few geodes in my life, but I had never seen anything like this underground geode on South Bass Island in Lake Erie. 

Discovered in 1897 when islanders were trying to dig a well, this geode is filled with massive celestite crystals comprised of Strontium Sulfate (SrSO4).

This geode has room for over a dozen people 

Surrounded by crystals!

The geode/cave is privately owned 

and is called the

Crystal Cave.

Crystals up close -- each crystal has 14 faces

This is the largest single crystal in the cave -- it weighs nearly 200 pounds

These are the largest known celestite crystals in the world.