Five Facts About Michigan Greenstones

Five Facts About Michigan Greenstones

The Greenstone is an intricate stone certain to catch the eye of any passerby. Set in pendants and rings, there are many Greenstones in our shop to choose from! Here are five facts about this fascinating stone.

1) Michigan Greenstone is Michigan's Official State Gemstone

Most people recognize the Petoskey Stone as Michigan's mineral representative, as it is Michigan's official state stone. However, in 1972, the Michigan Greenstone was officially declared the state GEM.

Five Facts About Michigan Greenstones

2) The Michigan Greenstone has many names

The gem is also known as the "Isle Royal Greenstone" due to it being most commonly found on the island. Though collection of these little gems on Isle Royal is now illegal, they can be found as small rounded pebbles along the shores of Lake Superior. The mineral name of the greenstone is Chlorastrolite. In Greek, Chlorastrolite means " green star stone."
Five Facts About Michigan Greenstones

3) Greenstone can only be found in the Keweenaw Peninsula

Even though Greenstone collection is prohibited on Isle Royal, the gems can still be found in the copper waste rock piles of the Keweenaw Peninsula of the Upper Peninsula. These mainland stones are found embedded in Basalt and are often larger and darker than the Island stones. Often possessing large chatoyant cell structures, the patterns are bolder as well. The identification and extraction of these mainland stones is a difficult process, but well worth it. 
Five Facts About Michigan Greenstones
Five Facts About Michigan Greenstones

4) Isle Royal Greenstones can be found in the Keweenaw

Isle Royal Greenstones aren't necessarily better than mainland stones, but they're naturally tumbled by Lake Superior as they travel to the mainland. This gives them a bit of polish, and makes them easier to find. Inferior stones are quickly eroded on the journey, leaving the best selection of gems to choose from. Mainland stones, however, can offer larger pieces with more complex patterns.
Five Facts About Michigan Greenstones

5) Often the "island stones" feature pink Prehnite

Also known as U.P. Thomsonite, this mineral gains its unique color from copper within the center of the inclusions. Some Greenstones have quartz or calcite centers, while others are hollow. The color and pattern tends to change throughout the depth of the stone as well. All of these factors make cutting and sanding the gems tricky, and only skilled stone cutters should attempt the process.
Five Facts About Michigan Greenstones

Set in pendants and rings, there are many Greenstones in our shop to choose from!

Five Facts About Michigan Greenstones
Information sourced from Keweenaw Gem & Gift