Isle Royale Greenstone: Facts, History, Jewelry, & Where To Find


Isle Royale Greenstone

(Image Credit: Lake Superior Magazine)

Many people enjoy using the Isle Royale Greenstone to make jewelry, where its blueish green color creates a distinctive piece. However, there is much more to this gemstone than its beautiful coloration. As we’ll see, there is a lot of interesting facts and stories surrounding this gemstone. Today, we’ll discuss some of these interesting facts about this gemstone which, despite its beauty, many people don’t know much about.

How Isle Royale Greenstone Was Formed

Let’s start by talking about the best place to find these gemstones. However, to do that we need to understand how they were formed. Billions of years ago, a tectonic shift occurred that caused a depression to occur in North America. This caused lava to flow up through the earth’s surface. Eventually, the lava hardened, leaving holes in the basalt rocks. Nutrients like copper filled these voids. Over time, the basalt split apart into the thousands of tiny gemstones that we see today.

Where To Find Isle Royale Greenstone

Isle Royale Greenstone, known by the scientific name Chlorastrolite, are found on the beaches of Isle Royale and the Keweenaw Peninsula. The gemstones found here tend to be of high quality. This is because nature has helped destroy poor material, such as gemstones that are hollow. It should be noted that there aren’t any major deposits on the mainland Lake Superior, however, you might be able to find some small, isolated pockets of gemstones.

While the gemstones found on the mainland are of more mediocre quality, they can still make great jewelry pieces. You will need to process them more extensively. Another exciting aspect of these gemstones is how they were first discovered. 

The Discovery Of Chlorastrolite

The Isle Royale Greenstone is part of the Pumpellyite family. The mineral was initially discovered in 1901. However, the first systematic study was conducted in 1920 by Charles H. Palache. He wrote a report on the data he found and sent it to B. S. Butler. However, when he read the report, Butler didn’t like the name Palache gave to the material and rejected the report.

In response, Palache crossed out the previous name and re-named the material Pumpellyite to honor the geologist Raphael Pumpelly. This saw his report accepted and published by Butler. 

Turning The Greenstone Into Jewelry

One of the best things to do with gemstones as beautiful as this turns them into head-turning jewelry pieces. However, this process may be more complicated than you realize. These gemstones are rated between five and six on the hardness scale, which measures how difficult it is to cut the gemstone. This hardness level means that they can be cut into various shapes to suit a jewelry piece.

It can be challenging to polish some of these gemstones, as they might have a hollow center. Another common difficulty is some mainland gemstones may have chlorite, which can make the stone’s patternless attractive. Also, jewelers can remove the top of the layer of the rock to reveal a different pattern. However, there is no guarantee that the new pattern will be better than the old way. 

The Rising Popularity of Isle Royale Greenstone Jewelry

While this type of jewelry has always been niche, there was a time when it was quite popular. In the mid-1900s, socialites in New York started wearing the gemstone prominently. Part of this interest was because they thought it could be an exotic new gem from France. However, when they discovered that it originated from Michigan, interest in the gem dropped again.

Today, the gem remains to have a relative niche interest, despite its beauty. The chances of finding a gem that you can transform into a jewelry item are meager because these gemstones are increasingly hard to find. 

The Difficulty In Finding This Rare Gem

The chances of you finding an Isle Royale Greenstone is low. There are a few reasons for this. First, it was made illegal to collect the gemstone from Isle Royale in 2000. While you can still spot plenty of gems along the shore, it is illegal to remove them from the national park. There are still some waste rock piles at the Keweenaw Peninsula where you hunt for these gemstones. However, these waste piles are increasingly being bought by private owners. Also, many of these gemstones are very small, which makes them difficult to spot.

This increasing rarity has made these gems more valuable. Despite their beauty, the Isle Royale Greenstoneis relatively unknown internationally. This means that you can buy a piece of jewelry made from this gemstone for a relatively affordable price. To recognize its beauty as a piece of jewelry, Michigan made FIsle Royale Greenstone it’s a national gemstone. 

Becoming The State Gemstone Of Michigan

Finally, in 1972 the Isle Royale Greenstone was officially made the state gemstone of Michigan. Once the bill was introduced to parliament, it quickly gained support, with the move being made official on the 22nd of February. However, there were a few politicians who weren’t happy with the proposition. For example, Anthony Stamm, a senator from Kalamazoo, said the raw form of the gemstone looked like the gravel he put on his driveway. Another senator said that despite the gem’s beauty, his wife would still prefer to wear diamonds. Today, though, despite passing the bill passing parliament, most people are unaware that the Isle Royale Greenstone is Michigan’s national gem. 

The beauty of the Isle Royale Greenstone is astonishing, which is why Michigan made its national gem in 1972. Despite this, many people don’t know much about the gemstone. To help educate you, we discussed many exciting facts about this gemstone, such as how it was formed, where it can be found, and how its family came to be known as Pumpellyite. Hopefully, you enjoyed learning more about this gemstone. It is also hoped that this information will give you a greater appreciation of this gemstone. There are plenty of jewelers who offer pieces made from this gemstone so that you can own a piece of Isle Royale Greenstone.


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