After the Keweenaw Week copper collecting activities, Dr. Chris Stefano was kind enough to escort members of the Walker Mineralogical Club to the old Manganese Mine near Copper Harbour, MI. Back 150 years or so ago, about 1200 tons of iron/manganese mineralization was mined from surface and underground workings to be used for iron production. Unfortunately, the mineralization was not suitable for iron production. Interesting mineralization there, if you look closely. Check out the locality in mindat.org, if you'd like to see excellent photo's of all of the minerals. Here are pics of the trip plus an ancillary geological trip. I'll post pics of minerals that I've found when I clean them up!
View of Copper Harbour
Copper Harbour was the site of the first copper mining operation back in 1844 or so. In addition, in the early 1880s, this old port was also the site of an attempted iron mining operation, which we visited to collect rare iron-manganese minerals from the old dumps. Today, Copper Harbour is a tourist town with artsy-crafty stores and lots of boating activities.
Rock Dump Collecting
This is how you collect at the Copper Harbour Manganese Mine. It is all about looking for iron/manganese rich chunks and looking for traces of the rare minerals. The mcfallite is readily visible as radiating, lustrous brown aggregates in the black manganese oxides with calcite.
Here is an example of macfallite, 3mm across. This one has had the calcite etched out from around it with weak acid. Nice crystals! Haven't found any orientite, yet.
Here is another example of a nice 3mm spray of macfallite crystals but this time embedded in calcite, as they are found. This is one of the rare manganese minerals we were searching for at Copper Harbour.
Dr. Chris Stefano
Chris Stefano lead us to the tip of the Keweenaw Peninsula to a little bay that was a wonderful geological excursion. The various, steeply dipping sediments are well exposed there, showing differential weathering. Great place for swimming and kayaking!
Handfulls of Berries
I think the best part about this mine visit was the multitude of raspberry plants laden with raspberries. The berries were exactly ripe and just fell off of the branches to the ground, if you weren't careful. It was easy to eat many handfuls! I ate lots of these! 🙂
Knows His Rocks
Dr. Stephano exhibited a deep knowledge of rocks, particularly water-skipping stones, as he demonstrates here.
It is the peak of berry time in the Upper Peninsula of Michigan with an abundance of Blueberries, raspberries, huckleberries and saskatoon berries. Had a good number of blueberries for my snack.
This little cove had an excellent exposure of stromatolite fossils exposed at the interface of the conglomerate and underlying shales. The stromatolites are interpreted by some as being of freshwater origin, forming in lakes close to a billion years ago and then during changes in climate/elevation, etc., were inundated andcovered by sediments, in this case the Copper Harbour Conglomerate. These are some of the oldest fossils in the world, close to a billion years old. Pretty cool!
Here is a picture of some of the stromatolites up close.
If you are a mineral collector and happen to be in Copper Harbour, you have to drop into Swede's. He has a very large array of copper and related mineral specimens, some pretty good! I found his prices kind of high but there is no doubt he has good mineral specimens.
Swede's Copper Specimens Display
Here is a look at Swede's coppers specimens for sale display. Lots of 'em!
Copper, Quincy Mine, 14.0cm across
What an interesting specimen from this famous mine! All copper in an interesting sharp crystal aggregate.
Copper, Quincy Mine, 2.0cm across
This crystal is small but potent! Look at the forms on this crystal. Amazing!
Silver, Copper, Wolverine Mine, 6.0cm across
Specimens like this are wonderful. Relatively sharp silver crystals on native copper, often oriented. An exemplary example.
Silver, Calcite, South Hecla Shaft #2, 10.0cm tall
We often see copper crystals associated with calcite but less so silver crystals. It is odd on this one though, that it seems to be a group of silver crystals, although the colouration of the calcite crystals indicates they are included with copper? There is copper in the specimen, as well as silver? What is going on!?
Silver, Copper, Kearsarge Mine, 14.0cm across
Wow! Not a great photograph but wonderful darkened silver crystals on native copper.
Silver, Wolverine Mine, 3.0cm across
A beautiful little cluster of sharply twinned silver crystals.
According to lore, some copper miners used to work on their own after hours chiseling silvercrystals (NOoooooo!!!!) off of native copper in order to sell the silver for an additional wage. I have seen examples of this kind of handiwork where there is a just a chisel-mark smear of silver adhering to a copper lump where once there was a nice crystal. 🙁
Zircon, Smart Mine, Brudenell Twp, Ontario, 6.0cm across
The A.E. Seaman Museum is NOT just about copper, silver and minerals of Michigan. The collection also has excellent specimens of various minerals from around the world. Here is a good example that I lust after. A dark red geniculate twin of zircon from the famous Smart Mine back home in Ontario. Pretty darn rare!!
It just so happened that a local group holds an excellent swap meet during Keweenaw Week. Almost every table was loaded with local gems and minerals. Some excellent copper crystal specimens were available here!
Copper, Central Mine, 15.0cm across
Wow! We don't see specimens like this very often! A large cluster of sharp copper crystals up to 30mm or so in size.
Copper, Calcite, Quartz, Pumpellyite
I managed to pick this one up at the mineral show that CCRMC puts on at the end of Keweenaw week. Such a classic Keweenawan copper specimen! The copper is enclosed in air tight calcite which prevents it from tarnishing like the other copper outside of the calcite. Just great.
Copper, Central Mine, 6.4cm tall
This specimen has had most of the calcite removed to reveal excellent divergent groups of copper crystals. Picked this one up at a copper sale on a fellow's front lawn on the main street through Laurium, MI.