Isle Royale Greenstone: Exploring Michigan's State Gemstone

By Jordan DeWitt

Isle Royale Greenstones are forever going to be a part of Michigan's rich cultural and mining history. Most of the gem-grade greenstones used in jewelry today come from tailings of old mines in Michigan's Keweenaw Peninsula. Searching for these mysterious and rare greenstones has always been a challenge to people.

This book is for anyone interested in planning a trip to find greenstones and offers important insights into discovery, identification, trip-planning, and advance polishing and finishing techniques. Greenstones are Michigan's best-kept secret and are a treasure worth seeking. Along your search for this incredible gemstone, the real treasure will be the memories made along the way. We live in a modern day when it seems like a treasure hunt is out of reach for ordinary people, but a treasure hunt might be closer than you think. Michigan's northern country has so many treasures waiting to be found. The Isle Royale Greenstone could be the reason for your next adventure.

• Language: English
• Publisher: Newman Springs Publishing, Inc.
• Release date: Aug 1, 2023
• ISBN: 9798887636399

Book preview

To Bruce, my amazing father and friend

Photo of greenstones resting on the shores of Isle Royale National Park.

Introduction

The excitement and thrill felt on a treasure hunt can really make an older person feel young again. The sense of wonder and adventure grabs your heart in a youthful way (e.g., the way you felt when you visited an amusement park for the first time or your very first Easter egg hunt. Whatever that feeling is, it’s contagious and spreads to everyone around you.

If it sounds like a child is writing this portion, it’s probably because it’s true in a way. When I think of a trip to the Keweenaw Peninsula to look for greenstones, the kid side of me is awakened. The question of what we might find is what gives this youthful feeling such credence. What Michigan treasures will we come home with this time? Will the places we looked at before have any more greenstones to give up this time? The suspense is almost too much to take the night before you get into the truck and go.

This feeling is shared among rock hounds. It’s normal to see people of retirement age start collecting rocks for the first time and have a childish way of describing the feeling when they look for rocks. What they are describing is a new and elated sense of adventure. This sense of adventure could have been twenty years in the making for some people working a career job and wondering the whole time if there was something more. It’s unclear what’s more rewarding to see—a child with a new elated sense of adventure or an older person with this feeling. It may just be both.

Michigan rock hounds are one of the most enthusiastic groups of rock hounds. They really care about their home state and have a lot of pride in the place they call home. When people discover looking for rocks and minerals as a hobby for the first time, they certainly have the upper hand in Michigan. The lapidary community has a great reach, and the number of places to search for rocks and minerals is endless. Greenstones are at the top of the list for many rock hounds. They are highly prized and cherished among rock hounds in Michigan.

So when it comes to a treasure hunt, there is real treasure to be found in Michigan. The treasure could be a greenstone or other rocks and minerals native to this great state. Rockhounding in Michigan is for everyone and really is what you make of it. It can be a special and rewarding hobby that gives you amazing memories and a sense of adventure.

Portage Canal Lift Bridge. This unique lift bridge connects the two cities of Hancock and Houghton. Hancock is toward the north side of the bridge, and Houghton is toward the south side of the bridge. The body of water that separates the two cities is known as Portage Lake. It is the only method to cross into what’s known as Copper Island to locals.

The National Park Service employs this passenger vessel named Ranger III to carry passengers from Houghton, Michigan, to Rock Harbor, Isle Royale. The Ranger III is one of two passenger vessels that bring people and goods to Isle Royale National Park. Workers for the National Park Service are seen here in this photo, loading supplies needed for operations at Isle Royale National Park. Almost everything needed to support the island’s operations are brought to the island by the Ranger III.

Welcome to a chance of discovering some long-kept secrets surrounding Michigan’s mysterious and most beautiful treasure, the Isle Royale Greenstone. This book can serve as a helpful guide in planning a trip to Copper Country and discovering for yourself your very own greenstone treasure. Also in this book is a large collection of color photographs illustrating this amazing mineral. Knowing what greenstones look like is the first step to finding one.

Chlorastrolite is the scientific name given to the mineral we know as greenstone. It was and sometimes still is referred to as pumpellyite in the scientific community. Turtleback is an affectionate name given to the mineral because of its tendency to look like the back of a turtle when polished. Greenstone is the simplest way to refer to the mineral, and for the purpose of this writing, I wanted to fully acknowledge the scientific names given to the mineral while keeping this writing simple to read and understand.

Pumpellyite, chlorastrolite, turtleback, and greenstone are all names the people of Michigan call the state’s official gemstone. It’s believed that the early use of greenstone by Native Americans was much the same as today. These little green stones were traded as beads for jewelry and other decorative items. Even without the use of precision diamond cutting equipment, greenstones can be quite shiny and chatoyant, which means the light moves in the stone when viewed from different angles. When the greenstone is moved or rotated in the sunlight, the lighter-green areas of the stone turn darker, and the darker areas of the greenstone turn lighter. It’s quite cool and fun to look at for the viewer, and it’s what makes the greenstone so desirable.

Because greenstones are formed in the voids left in basalt by escaping air during the cooling of volcanic rock, greenstones are the size of the air pockets left in the cooled volcanic rock. To make it simple to understand, the larger the air pocket, the larger the greenstone that was formed. Conversely, the smaller the air pocket, the smaller the greenstone. Photographs in this book should help with describing this in further detail. Because this process is completely random, the size and shape of greenstones can also be random, but a natural greenstone is generally round in appearance.

Paying passengers can also elect to bring their own boat to Isle Royale for a fee. The boats are lifted onto the Ranger III using the crane seen in this photo. The boats are then secured with heavy straps for the sometimes-rough ride to the island. Generally, the calmest trip to the island is in June and July, with the smallest waves expected. The larger waves are normally in the early spring and late fall.

This is a picture of the Portage Canal Lift Bridge from the Ranger III as it departs for Isle Royale National Park.

Isle Royale greenstones are