As the Minnesota tundra thaws......

As the Minnesota tundra thaws, I find myself very impatient for warmer days to get out into the garage to saw rock.  Carol and I have picked up some rough lapis lazuli

April 10 and Minnesota is getting hit by the super snowstorm.....

April 10 and Minnesota is getting hit by the super snowstorm that is hitting the Midwest.  I feel bad for the robins that are here.  They look so cold bouncing around on the snow , all puffed up.... 

I need to change out 240 and 600 grit diamond wheels on the Cab King.  I have been putting it off.  The tumbler has rainbow moonstone at 600 grit.  Otherwise not much is new.

As the Minnesota tundra thaws.......

As the Minnesota tundra thaws, I find myself very impatient for warmer days to get out into the garage to saw rock.  Carol and I have picked up some rough lapis lazuli and oco geodes that just invite sawing.  I need to clean out our 10" highland park saw, as the oil is very dirty and sludgy.  That means using the tile saw after I put on a new 6" thin diamond blade designed for cutting agates.  I was advised to "take it slow and use LOTS of water".

In the meantime, I have been tumbling a batch of rainbow moonstone for several days in 200 grit.  They are starting to look nice and I can stare for hours at the little rainbow flashes as pieces hit the light as they tumble.  In case you as the reader haven't picked up on it, working with rock is a very meditative and mystical thing for me (Jim).  I can be totally focused for hours and before I know it 5 hours can have gone by. 

Here is a representative piece from a google image search of the kind of material in the tumbler.



  As always, I can't say enough about the Belt Inc. Lot O' Tumbler.  The results are fast using vibratory motion and the polishes are beyond compare.

Newest cabochon of fossilized dinosaur bone from Utah

Newest cabochon of fossilized dinosaur bone from Utah.  You can clearly see where minerals replaced the cells.  Most of this material is found in the Utah/Colorado area.  When the dinosaurs died, the bodies would be carried downstream and formed a dinosaur "log jam"-where the bodies were quickly covered with river silt.  I think Carol mentioned 20 million years ago for those events.  The Colorado/Utah area was a swamp at that time with many river systems running through it, not the dry and dusty land it is today.

Another new addition is a black obsidian cabochon with one snowflake in the corner.  I kept on getting my mug in the picture because of a high shine.  First world problem there....

....batch of 65 new cabochons

Time flies and no blogging has occurred.  Carol and I went through a rock lull period.  Oh the collecting never stopped (some would say hoarding) and Carol did a few custom orders and I did a few cabs, but not in the quantities we used to do.  It seems like the lull has been good for defining ourselves and what Pocket Rock Designs is about.  We decided that it is all about being eclectic and no one rock or piece of jewelry is ever the same as another.  It helps to have a vision.  Etsy sales have been good.

As for me, I have a hard time doing calibrated ovals all the time and find that the natural cracks and contours of the rock usually lead to the final free form shape.  We have branched off to include some new materials, including blue apatite crystals, rainbow moonstone, and 1 1/2 pounds of lapis lazuli.  The Lapis is gorgeous and I will post a before and after pic as soon as possible.  Expect to see some banded, agatized, fossilized dinosaur crap on here too.  I hope to be blogging every other day for now.  Besides reaching out, I think it is a great way to chronicle our journey.



Cab King cabochon machine with 6" diamond wheels!  Oh the Joy and Rapture! MEOW!

Carol has stocked up on beads, metal, a Foredom flex shaft, and items needed to make rings.  She is so creative and I can hardly wait until she gets some time to bezel, solder, and have a great time.  Last fall we invested in a Cab King for grinding and polishing.  Now that I seem to have finessed the finer points of operation, I have just completed a batch of 65 new cabochons which we will be posting to Etsy soon.  Having good equipment really makes the difference in quality.  Expect Operation "Stock up for the Northfield Artist's Walk Shows" to ramp up shortly.  I will try to get some photos on the blog, so stop in frequently.

What's in the Lot O' Tumbler now?
Lake Superior Agates 1 to 2"
Tiger Eye preforms
One fantastic piece of Binghamite
Snow Flake and Black Obsidian just to see how it goes

Here is a representative picture of some of the Lapis we bought:

Sudbury Basin-Ontario-making my case because I am a stubborn cuss....

The basin formed as an impact from a bolide approximately 10–15 km (6.2–9.3 mi) in diameter that occurred 1.849 billion years ago^[2] in the Paleoproterozoic era.

 

Debris from the impact was scattered over an area of 1,600,000 km² (620,000 sq mi) and traveled over 800 km (500 mi) away — rock fragments ejected by the impact have been found as far as Minnesota ^[3] (though models suggest that for such a large impact, debris was most likely scattered globally,^[4] but has since been eroded away). Its present size is believed to be a smaller portion of a 250 km (160 mi) round crater that the bolide originally created.

Help us identify Mystery Rock-dum dum dum (dramatic music)!

Carol's Etsy description says 

"The pendant is from a rock we aquired when we bought 3 cigar boxes of rocks that came from an estate sale. The rock is moss agate, the mystery are the metalic circular inclusions. I did some research and these may be iron concresions of some sort or lapilli. If you've seen this before contact us I would love to know for sure."

 

I, not being a geologist, looked up Lapilli and found on Wiki that Lapilli is a size classification term for tephra, which is material that falls out of the air during a volcanic eruption or during some meteorite impacts.^[1] Lapilli (singular: lapillus) means "little stones" in Latin.

 

What we hypothesize is that these lapilli flew through the air getting all roundy in the process, eventually falling to Earth.  Later a Quartz/Chalcedony solution enveloped these balls.  When the whole rock was cut into slabs the spheres became circular cross sections.  The cigar boxes of rocks came from an older gentleman who lived in Rochester, MN, but it is hard to know where this was collected.  I think it was collected from Northern Minnesota and that it originated from a meteor impact in Southern Ontario from a time I can't remember (I read about at the Minnesota Geological Society website).  Carol believes the spheres came from volcanic action.  She is probably right, but heck, we may both be wrong, so any help on this is appreciated.  No reward only credit on the blog and the everlasting glory that brings!

Northfield Riverwalk Market

Today we were at the Northfield Riverwalk Market selling our jewlery and cabochons.  The day was much sunnier than last time, when we got dumped on with a deluge of rain.  It was muggy and hot and we had a fun time talking with the people who came by to look or to buy.  Some were jewelry makers or had tumbled a rock or two in their day.  

Jim was in good spirits.  He had been in the hospital for a few days and had just been released yesterday (Friday 7/15).  I was surpised he wanted to come.  We had a lot of fun!!

General Store and Rock Shop in Oakaton, SD-Honeymoon Memories

Oakaton, SD General Store and Rock Shop

The old Oakaton Feed Mill



Carol and I were on our Honeymoon traveling to Utah via I-90 through South Dakota.  We had gotten married in June of 2005 and I believe the Honeymoon trip was late June- early July.  We had not hit the Black Hills and I spotted this obscure sign that said Rock Shop next Exit.  I turned instinctively in the turn lane (not telling Carol what I was doing, only that it was "An adventure").  There was the sign for Oakaton, SD pop. 12 at that time.  What a charming semi-ghost town.  The general store used to have a much better rock shop back in the day, but evidently the husband and wife who had the place before had died and the rock selection had waned.  There were still nice specimens and a fair amount of fossils left, but the passion wasn't in the new owners.  The place had back buildings that showed what the place used to be like with an old bank, jail, blacksmith... and these spaces were filled with antiques for sale.  What was of more interest was the old run down feed mill with an abandoned set of Milwaukee Railroad tracks in front of it.  Evidently, the Milwaukee Road abandoned the track in the mid to late 1940's, but neglected to pull the rails.  As you can see by the picture, the cross bars are still there.  Years ago, someone from Hollywood came to Oakaton and filmed a movie that was never released.  This was a romantic trip and a very romantic stop.  Rocks, fossils, a single gas pump, old buildings, old set of train tracks set into the Dakota Prairie, and each other.  Meow.

Coming up on Oakaton from the north off I-90

Ancient Beauty - Mary Ellen Jasper

Mary Ellen Jasper comes from the Mary Ellen Mine in Minnesota.  Scientifically known as Collenia undosa, the microorganisms involved were likely to have been photosynthetic bacteria that were busily expiring oxygen that would ultimately constitute the modern atmosphere on earth during a time colloquially termed the “rusting of the earth”.



Polished Mary Ellen

 



Rough Mary Ellen

These microoganism colonies are called Stromatolites, these stony algae colonies built up layers and sometimes whole reefs.  Mary Ellen Jasper is the fossilized remains replaced in sedimentary rock, the beautiful filaments and layered polyps are one of the earliest life forms preserved today.  At over 2 billion years old, this primitive species is often credited with providing our oxygen rich environment.

You can still find Stromatolites today in such places as Shark Bay, Australia where they continue their billions of years old lifestyle.

Montana Moss Agate Treasures

Montana Moss Agate is the name given to the beautiful chalcedony found in the alluvial gavels of the Yellowstone River and its tributaries. It is From the Pleistocene age (10,000 - 1,6000,000) Found not in-site, but in gravel deposits.


A small area in Montana seems to have the best of this agate. Found in gravel deposits in the middle and lower Yellowstone valleys. Agates are found in both the present stream bed and in gravel terraces. 10 to 15 miles either side of the Yellowstone drainage. 

Rough                                                    Polished













Cabochons Jim has made from Montana Moss Agate

    

   

Hidden Treasure

Part of the joy of collecting is that you never know what you will find when you saw into the rock.  The rock shown above is cut from a piece Carol collected years ago from the dump piles of the Old Hickory Mine in Utah.  The Old Hickory mine was once mined for copper.  The dump piles contain rock deemed not worth much-namely the offshoots of copper like azurite, cuprite, and chrysocolla to name a few.

The rock I cut into had streaks of chrysocolla along with calcite (the green above is the chrysocolla and the white is calcite.  What I wasn't expecting was a copper based mineral called covellite.  Covellite is the blue and it has pyrite in it so you get the blue/gold shimmer.  Covellite is rare and increasingly sought after.  The best source was the old Leonard mine in Butte, Montana-which has been closed down since the early '70's.

It took awhile to realise what we had here.  This combination of minerals is atypical.  This is a heavy sucka due to the metal content-it will make a wonderful pendant for Carol.  

This is a video of a Lot O Tumbler in action.  The Rock Shed in Keystone, South Dakota posted this on You Tube.  They are tumbling a batch of Tee Pee Canyon Agate.  Tee Pee Canyon Agate is becoming harder to find and is almost as valued as Fairburne Agate.  Tee Pee Canyon Agate is native to the Black Hills.  

The tumbler has sticky strips so the machine can be mounted on a study block, silo stave, or solid cement floor.  It is relatively quiet, we have sound proofed a little before with a strategic placement of a towel.  The action of the Lot O Tumbler is caused by weights that are placed in the rotary cooling wheels and put in synch with each other.  Amakingly powerful for a 1/10 hp electric motor!  They are using big ceramic filler.  I use smaller pettets, as I feel they can get into difficult areas on the rock.

A little about rock tumbling....

I remember being 5 and getting a Montgomery Wards rotary rock tumbler for Christmas.  The joy and amazement in a child's eye seeing rough rocks turn into smooth semi-precious wonders!  The only draw back was the month + it took from rough grit to polish.

As an impatient adult, I bought a Lot O Tumbler by Belt Inc. out of good ol' Owatonna, MN (15 miles away).  This vibratory tumbler can take 5 pounds of rock from rough to polish in 5 days.  Talk about immediate gratification.  Now for the really rough material like Lake Superior Agates and such, I leave them in rough 200 grit for up to a week to help shape and get past pits and heat/cold fractures (these agates are a billion years old-imagine all the cycles of heating and freezing they have undergone).  Anyway, the overall process is better for my need for immediate gratification than the old rotaries.

The barrel has a capacity for 5 pounds of rock.  I have found better results using less rock and about 1/3 of ceramic pellet filler.  The ceramic will hold on to the grit-making for more and better grinding action.  Ideally, the rock should be wet enough so that grit sticks to it and the action of the gritty rocks moving over each other takes off the extra rock material.  Too wet and the grit won't stick and the action is reduced. 

Typically, I will wash the rock I want to put into the load to get off obvious dirt and smutz.  I then put the rock into the tumbler barrel with the rocks being wet, but not dripping.  I then add 1/4 to 1/2 tsp of 200 grit to the mix followed by 1/2 cap-full of water (I use a full cap of water if I am not going to be able to check on and wash the rock at the 12 hour mark).  One word of caution, try to use rock that are close to each other in the MOH's hardness scale.  The hard stuff like agate (MOH's of 7) will disintegrate the softer stuff like Rhodocrosite/Chrysocolla with a MOH's of 3.5 to 4.  Hard learned lesson is that less is more-less water and small amounts of grit. 

I start with 200 grit.  Any lower number tends to not stick to the rocks and sits at the bottom of the tumbler barrel.  The nice thing about the Lot O Tumbler is that the action is more gentle than other vibrating tumblers I have tried-yet it gets the job done.  You can also watch the rocks and media going around because the to can be removed.  It sometime is a meditative thing for me and over time you can see small changes to the rock.

After 200 grit, I go to a couple of days of 600 grit.  You can do it with one day, but the longer it goes at this stage, the better the polish at the end.  Another hard lesson-more time and patience at the lower grits translates to a more amazing mirror finish at the end. 

Next comes a fine 1200 grit.  This has the consistency of powdered sugar.  The final is a day or two in Rapid 61 aluminum oxide polish.  No one really knows the secret of Rapid 61, as the company holds the recipe dear, but it produces an amazing polish.  At the end, I put a drop or two of dish soap in with the rock.  After an hour the rock gets pretty clean and there is far less washing and tooth brushing polish from out of the way crevices.  We cheat a little by putting the finished product (if harder material) into a small ultrasonic cleaner (about $45) 

I will post more later about rock tumbling and try to include some "Action footage" from the Rock shed in Keystone, South Dakota.  For now here is a picture.  We don't have a double barrel model but have 2 singles we have going most of the time.  The oldest one has run almost constantly for over 2 years!



Twin Barrel Lot O Tumbler on the left and Single Barrel Lot O Tumbler is on the right.



Northfield Riverwalk Market Fair

Come see our creations in person

July 16th, August 6th, 20th, 27th, September 17th and October 15th




A century ago, visitors standing on the shores of Northfield's historic Cannon River would have witnessed the colorful sights of a thriving hub of commercial enterprise. Today, a summer Saturday along the Cannon is equally lively, but the business transacted has a distinctly family-friendly feel! Riverwalk Market Fair provides visitors with ample opportunities to socialize and shop for outstanding examples of our region's fine ceramics, original paintings and prints, jewelry, and unusual fine craft items. Choose from a bounty of local and organic produce and cut flowers, as well as artisan breads and pastries.

We invite you to explore Riverwalk Market Fair to chat with our local artists, discover everything from rutabagas to roses for your table, and be entertained by open air music. We guarantee you'll be glad you did . . . and will be tempted to return again and again to experience the art of a summer Saturday!

http://www.riverwalkmarketfair.org/