About Michigan State Gemstone

This is the Michigan State Gemstone from Isle Royale Greenstone Jewelry

Isle Royale Greenstone (Chlorastrolite)

Michigan designated Isle Royale greenstone (Chlorastrolite) as the official state gem in 1973. Chlorastrolite (a variety of the mineral pumpellyite) is a bluish-green stone with a pattern of slender, star-like crystals which results in a "turtle back" pattern. Some Chlorastrolite includes other minerals, the pink parts are identified as thomsonite).

Isle Royale greenstone (sometimes called Green Starstone or Turtle Back in Michigan) is usually found as bean-sized, rounded beach pebbles (collecting Chlorastrolite from Isle Royale National Park is now prohibited since 1998). Polished stones are used for stickpins, rings, earrings, cufflinks, pendants, and sometimes incorporated into inlays and mosaics.

 Petoskey Stone is the Michigan State Stone, and Isle Royale Greenstone is the Michigan State Gemstone

 Isle Royale Greenstone are so striking with their stunning chatoyancy and handsome alligator-like pattern. People think of diamonds as rare, when, in fact, they are artificially scarce due to lack of free market sales and controls.

Michigan Greenstones, on the other hand, are a one-source gemstone. Nowhere else in the world are Greenstones found other than in Michigan’s Keweenaw Peninsula and on Isle Royale National Park, where they are illegal to harvest. Chosen as Michigan’s State Gem, the Greenstones represents Michigan uniqueness due to this limited accessibility but also means it is not well known outside of Michigan residents.  In fact, many outsides of the Upper Peninsula are not familiar with it!

Recent depletion of many of the mine waste piles in the Keweenaw to use as road fill is making the Greenstone supply even scarcer.  There are very few, non-private waste piles still available for the Rock enthusiast to pick up a Michigan Greenstone. Not all piles are worthy of seeking Greenstone in. There is expected a big spike in the Greenstone prices over next three years. Now is the time to buy Greenstone, especially quality ones with good patterns and coloration.

From all the Isle Royale Greenstones found only  2 or 3 out of a hundred will be gem quality.

All of our Isle Royale Greenstone came from private collections from Isle Royale collected before 1935 - We use no inland collected stones in our sales or jewelry. We still purchase private collections if anyone is interested in selling theirs please contact us: