Da Yooper's Rockhound and Lapidary Guide to
A zeolite, Thomsonite is relatively widespread Copper Country mineral and is found as an amygdule filling in the basalts of Michigan's Copper country, although it is usually not associated with Copper. It can sometimes be found in seams or veins. It is one of Michigan's Copper Country minerals that is often used as a gemstone in jewelry.
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Huge Thompsonite in
mine waste rock
Da Yooper's Quiz
What Mineral from
the Upper Peninsula of Michigan is rapidly becoming
popular in the Lapidary Arts field as a Carving Material?
What is the name
of the Semi-Precious Gem Stone chosen as the Official
Michigan State Gem?
The first life on
earth was a Blue-Green Algae that formed what kind of
Name a highly
collectible and famous semi-precious gem stone found on
the shores of Lake Superior?
|Thomsonites are often found
in the waters and on the shores of Isle Royale and in
some areas of the Michigan copper ranges of Lake
Superior. Many of the old tailings of the Copper mining
era have Thomsonites in them. Look for white chalky,
small round or almond shape nodules in the poor rock. The
problem of course is getting them out of the rock without
damaging them. Sometimes they will have weathered out of
the rock and can be found lying on the ground. (These
usually will be soft and sometimes not much good, but
occassionaly a good one will be found.)
Thomsonite Hill at Pole 30 on the road from Deleware to Eagle Harbor is famous for its Thomsonite. I have heard that the property has been sold, so check first before digging. The road cut at the crossing of Owl Creek is another place to dig Thomsonite. You will see the small white nodules that have weathered out of the rock. I have had best luck on the east side of Owl Creek. Also, check the road that goes into Copper Falls at the Y and to the left near the top of the hill. This is the same ridge as the Thomsonite Hill area.
Thomsonite specimen as a rule, are quite small. A little finger nail-sized stone with good radiating pattern can be considered a nice specimen. Thomsonite larger than this possessing a good radiating pattern are extremely hard to find.
Be sure to visit our Auction site for Thomsonites.