Monthly Archives: March 2009

Thomsonite and Prehnite

Rockhounding the the Keweenaw Peninsula of Michigan is one of my summer highlights. A distinctive set of stones are found there, many related to the presence of native copper. In this article I would like to talk about thomsonite and prehnite which are different stones, but sometime share the same name.

True Thomsonite may occur in the Keweenaw Peninsula of Michigan, but is generally not associated with copper.

Thomsonite is a zeolite akin to minerals such as tanzanite. Thomsonite is a lovely pink stone sometimes featuring “eyes” and chatoyant sprays. The very best has always been associated with a small area near Grand Marais, Minnesota along the north shore of Lake Superior. The collecting area in that location has been closed to the public for many years, but Thomsonite pebbles still roll up on the beach near Grand Marais. The difficulty lies in most of the beachfront property being private property.

thomsonite

Most of what we use to refer to as Thomsonite from the Upper Peninsula is really copper-bearing Prehnite, or what is sometimes referred to as Patricianite. If you find what you believe to be Thomsonite and it contains specks of copper, it probably is Prehnite. The inclusions in the Prehnite are endless and create lovely pastel colors. Often “eyes” are present as are variegated type feathery patterns. We refer to these gemstones on our website as U.P. Thomsonite (this is what the locals call them also).

U.P. Thomsonite, in my opinion, is the most remarkable gemstone found in the Keweenaw. The striking chatoyancy and pastel colorations of this stone are something to behold. It is impossible to photograph the chatoyancy of true Thomsonite and U.P. Thomsonite as you really need to move the stones back and forth to see this effect. Thomsonite is much more expensive and scarce than Prehnite, but many people find the U.P. Thomsonite more attractive.

Good, jewelry-grade Patricianite is still hard to come by. It took me ten years to locate a spot to dig this wonderful stone. The locals will not easily give up their best rock hunting locations, so you may be on your own when it comes to finding U.P. Thomsonite.

Our website features some of the finest Thomsonite and U.P. Thomsonite available.

My Short Sword

The idea for a sword began when I made jewelry for the wedding of some of our friends, Chuck and Debbie (not the same Debbie whose jewelry I have been recently blogging about).

Chuck is one of the handiest guys I know, and one of his many skills is Blacksmithing. Debbie and Chuck are involved in Medieval Festivals in a couple ways. Chuck makes chain mail, knives, and swords as close to those from those olden days as you can find. They also have a family musical group called Evergreen that often plays at these festivals on period instruments.

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The wedding was a costumed Medieval wedding for their son and his new bride. I made custom pendants of beautiful blue Pietersite for them. I also made a sheriff’s star for another son. The idea of trying a sword came about as a barter between Chuck and I.

Chuck tells:

Originally, the blade was to be a standard 30 to 33 inch sword. The steel was part of a leaf spring from a late 70’s to early 80’s vehicle, usually good steel for this sort of thing. The tang was drawn in the forge, then the blade was drawn with hammer and heat. I was using a charcoal forge instead of coal or gas. I’ve been using charcoal for a more authentic effect at Renaissance and SCA events. The blade was 80 percent complete when I noticed a small flaw in the steel at almost exactly the middle of the blade down its length. I tried everything I could to eradicate the blemish. I surmised that being from that period of time when recycled steel and much of it coming from inferior sources was the cause. It was very disappointing as I already had much work into this blade. I decided to cut the blade short and to finish the project as a short sword. These were also typical weapons throughout the Middle Ages, made for close-quarter and two-handed fighting. I was able to get rid of the blemish and the sword turned out to be quite well balanced and looks great. The cross guard and pomel are of mild steel. After talking with Don, the swords future owner, on the design and layout of the fittings I went back to work on the shaping and finishing of the fittings.

As Chuck was smithing the blade and butt of the sword, I was thinking about what jewels might have been in a sword of that time. A little library research delivered limited results. Certainly carnelian agate may have been used as well as other agates and maybe some rubies, sapphires, and garnets. I decided that I should add some chrysoprase. Although it was certainly not used in these swords, as the best material comes from Australia, I liked the color. It resembles aventurine which may have been used in Medieval times.

Now I had a new problem. I had decided on square cut inlays. How do you cut out square holes in steel? Certainly not with my rock-polishing equipment. I asked my neighbor Mike if he could make square holes in the sword butt so I could insert gems. I think Mike was getting used to all my wild ideas by then and he suggested the answer was a carbon burn out technique.

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I got the sword back from Mike, cut the stones to precisely fit, yet I was not happy with the carnelian agate stones in their cut out holes. Because they were transparent, the dark depth of the metal background in the holes came through the gems and you could not even tell they were golden in color. They just did not shine. I tried a couple things to brighten the stones including painting gold fingernail polish in the holes. This did not work because the paint was too thick. I had a couple other lame ideas, but I finally thought that gold leaf might work if I could find someone who did that! I stripped the fingernail polish out of the holes and took the sword to a local sign shop that does gold leaf. I think the owner had fun with this project. He told me his employees seemed to work better when he had the sword in his hand! The gold leaf worked like a charm and created a glow that comes through the stones and makes them look noble and amazing.

I returned the sword to Chuck for final polishing and a placement of a bone handle on the unit.

Chuck again:

The two bone slabs were fitted over the full tang and “let in” to the crossguard to insure stability. The slabs are epoxied with a little bone dust for color matching mixed in. The steel parts were blued after all fitting was complete. The end of the tang is threaded and the pommel is tapped so that the parts may be removed if necessary. It took almost two years to complete this project as the different phases of construction were accomplished by different individuals. All in all, I am very pleased with how it all turned out.

Chuck Sieting

OK, it took Chuck over a year, and it was most fun jabbing him about finishing the sword whenever I saw him around!

I received the beautifully polished sword back eventually and I am pleased to own it, as it is a real show piece.

I added up how much this piece of art might cost with everyone involved and came to a $650 price. So if you want something like this, we can do it, but it won’t be cheap. And you know that though it might be a short sword, but it had a long construction!

Native Copper

The largest and greatest deposits of native copper ever discovered occur in Michigan’s Keweenaw Peninsula. These copper deposits have been exploited since prehistoric Native Americans used hand tools made of rocks to chisel out the almost pure copper from exposed surface areas.

Native copper is very rare throughout the world. Copper deposits are not ordinarily comprised of large masses of almost pure copper. The copper from the Keweenaw is most often “polluted” with silver, making it even more conducive to electrical uses. copper

The habits of copper growth are too numerous to list, but one of the most coveted by Keweenaw-area collectors are silver and copper combinations known as “half-breeds”. Beautiful crystal copper formations are also sought, as are copper-included minerals such as Datolite, Prehnite, and Greenstone.

The history of the Copper Country is interesting to study and many wonderful books have been written on the subject.

We sell native copper, both cleaned and raw, as well as special pieces like the aforementioned half-breeds. We also have raw chunks of copper that have been through the hammer mills and most likely carried off by miners in their lunch pails. Another interesting throwback to the copper days is Firebrick, almost impossible to find now. Bricks lined the smelter walls and over time became permeated with molten copper. After the mines closed, some of this material was rescued when the smelters were closed, back in the 1960’s.

Currently no producing mines are left open in the Keweenaw, the tunnels are flooded, and the discard piles are gradually being crushed for road gravel. I have seen collecting opportunities in the Keweenaw declining rapidly over the past 20 years as old mine discard piles disappear, and collecting areas revert to private property. Much of the gemstone material I used to collect is now impossible to obtain in the field. Now is the best time to invest in jewelry and specimens from the Copper Country while the prices are still affordable.

A few mines are still open for tours: the Delaware Mine between Calumet and Copper Harbor, the Adventure Mine near Ontonagon, and the Caledonia Mine, also near Ontonagon. The Caledonia Mine offers collecting opportunities both underground and on the surface by appointment. Specimen collecting is still underway by the owner of the Caledonia, Rich Whiteman and his crew.

We offer the very best jewelry manufactured from rare copper country gemstones. Many of the materials we use are purchased from collectors in the area or found by us in our rockhounding forays to the area each year. Our beaded bracelets combine many U.P. stones including agates, epidote, and kona dolomite as well as the copper-related stones. Our Datolites sometimes have great bits of copper in them–Copper Datolite with Epidote, and Datolite, Copper Lightning. We use only the finest quality rough materials to create our finished products, and truly believe our U.P. jewelry line is the finest anywhere.

The Evil Spider

On occasion I find unusual patterns in the stones I cut. I expect to see beautiful landscapes in the Biggs and Deshutes Jaspers, but it is a rare treat to find a picture in other stones. One of the advantages of cutting my own cabochons is that I can pick out these unusual pictures. I have found great pictures in Petrified Wood and sometimes in agates (like the Parrot). In this Butterfly Jasper I saw an evil spider.

I guess it sort of looks like the alien craft from the original War of the Worlds movie also.
With a nice wire wrap and a great image, this piece was also purchased by Debbie, another fun addition to the “Debbie Collection” of Snob Appeal Jewelry wire-wrapped pendants.