Rock Tumblers Redux: Looking at the Stages of Tumbling

Several weeks ago, I posted an entry to the blog about how to work with your new rock tumbler (this of course assuming that you had received one at some point). Six weeks into my own experimenting with rock tumbler, I'm back with a few lessons and things that I've gleaned from my own experience, which I hope will be helpful to you.

Tumbling is typically a multi-week process, depending on the materials that you choose and the kind of polish that you are hoping to achieve. The choice of materials is important, as tumbling something rather hard with things that are soft will tend to result in the soft things being smashed down into tiny bits. To be certain of the hardness of the materials with which you are working, it's essential to have either a good rock & mineral field guide (I've got about a half dozen), all of which will give you the hardness of most anything you are likely to be tumbling, as presented by the Mohs Scale of Mineral Hardness, which ranges from 1 (talc), to 10 (diamond). If you pick up a field guide and it doesn't have this basic information, put it back on the shelf and find something else. You can also use online resources to determine the hardness of your material: the most thorough of which I am aware is Mindat, which is currently a free site (although with a free registration you can have access to more features). Even with care taken in selecting which minerals and rocks you tumble, you should still expect for anywhere from a quarter to half of the volume to disappear into your slurry bucket.

Polish is also a consideration: some people will like their stones to have different lustres, so it does come down to individual taste. Personally, I want to see just how brilliantly reflective I can make some materials, so I am experimenting with a range of stone.

Assuming that you are indulging in a basic four week-long process, you will also want to choose your grits with care. Before I'd started working with a tumbler again - after a gap of many years - I had expected that four standard grits made of silicon carbide would be sufficient, and hadn't really understood the importance of the pre-polish and polish phases. I can now tell you that these are crucial (this probably should have been self-evident). The pre-polish and polish phases, both accomplished in my case with very fine aluminium oxide polishes, are essential... if you want your tumbled stone to shine, that is.

Time is also an important variable. Your tumbler should come with a guide, or you can find them on the web with relative ease (also in my last post). On my first attempt through the whole of the process, I allowed at least a week for each tumbling stage. This may have been overkill, but on the other hand, I was recently told of a man who left his rough in the final polish phase for something on the order of six weeks! This is probably unnecessary, at least at first. Follow the guides to begin with, until you will get a sense of which materials will require longer than others in the various stages. Again, this often comes down to personal taste.

One thing that is somewhat annoying is that, for the cleaning phase, the use of Ivory Snow flake detergent is often recommened, at least in North American guides. Unfortunately, this product no longer exists. However, if you can't find another plain, pure, unscented soap, the workaround is simple: find a bar of Ivory Snow soap (which does still exist), or any other basic unscented Castille-type soap (Pure & Natural also comes to mind), and use an old cheese grater to make your own flakes. It may help to dry the soap out a bit first - put it in a warm, dry place for a few days, then grate. You will now have soap ideal for use the cleaning phase of tumbling.

Rock tumbling seems, in the shiny new digital 21st century, like something of an anachronistic pursuit, and perhaps it is. But it is also one which connects us with the realities of making something, of doing something, rather than simply paddling around in the virtual pool. Hopefully, you will take as much enjoyment from it as I am.

New Merchandise from Tucson - Part 2

We have been able to purchase some exceptionally nice Lamna species teeth as well as Megalodon teeth while here in Tucson. The latter are very nice indeed in that they vary considerably in color rather then being just the run-of-the-mill black. For the Lamna teeth one must always look for the cusps on either side of the main tooth. If the cusps are missing the tooth isn't as valuable.

The Lamna teeth are almost always white to a light tan in color and are very sharp!

The Megalodon teeth are the right in these pictures and the Lamna are directly above on the left.

Below, on the left are teeth from the mosasaur species globidens. These were shell-crushing aquatic reptiles that died out 65 million years ago. Most of you are familiar with the more common mosasaur teeth we sell, but these are entirely different and much rarer.

Below on the right are ammonites from Madagascar. These have been polished to expose the sutures that marked the separations between the internal air spaces the animal used for buoyancy.

Finally, we have also been acquiring some minerals specimens, and for the first time we have purchased some polished quartz crystals about 1.5" to 2" long. These are pictured below.

New Merchandise from Tucson

Here are some photos of the merchandise we have acquired here in Tucson. First we bought some fossil fishes from the venerable, jolly and highly knowledgable Bob Finney. We bought three larger plates and 65 unprepped 4" to 6" "singles". The latter will be put in our Fossil Prep kits we. The former are pictured here; the first is a triple plate with two Knightia and a Diplomystus:

The above place is ~18" x ~14". Next is a 12" x 12" plate with a large Diplomystus:


Finally, we acquired a very nice Mioplosus and preditory perch that lived in the lake 55 million years ago. This plate is 12" x 8":

Those of you who really like Fossil Lake fishes from Wyoming should stop by the Beagle next week to see these pieces in person.

Where we stay in Tucson during the TGMS

For those of you who have not visited our the home of our friends, Joe and Cheri, in Tucson we wanted to show it to you. We have enjoyed Joe and Cheri's hospitality for 6 years during our visits to the Tucson Gem, Mineral and Fossil show. In fact, it was Joe and Cheri's insistence that we stay with them and visit the show back in early 2004 that first brought us here.

Anyway, to take a look, visit this web site: www.longrealty.com/AZ/Tucson/85718/homes-for-sale/5441-E-Gleneagles-Dr-46575313, and take a virtual tour of their home, which is now for sale. Any of you wishing to purchase a new home in beautiful Tucson could certainly do far worse.

We'll be on our way again today for more exploring and buying. Keep watching for information on the new merchandise we will be acquiring.

Also, please post any comments, especially if there is something in particular you would like for us to acquire.

Let's take a trip to Utah to collect Trilobites

Well, while here at the Tucson Gem, Mineral and Fossil Show Carol and I found a group through which we can offer a trip for 10 to 12 persons to dig for Trilobite fossils in Western Utah. We'll have lots more information here, as well as on our web site, but the important thing is, "all fossils discovered during the (dig) belong to the person who discovers them! (n)o mater how rare or valuable they may be." We want to offer this trip to our Beagle Society and Science Club members and families first.

Those of you who went on the Great Montana Dinosaur Hunt will recall that we could not keep anything that was of significance to the permit holder. However, just like that trip, HMS Beagle will be handling all of the trip details including lodging, meals, access to the collecting site (over 300 sq. miles) and more. There will be bonfires each evening, fantastic scenery (the West Desert of Utah), workshops on digging techniques and field curation of specimens, and at leaast 20 different species of Trilobites can be found on this largely unexplored land.

The two gentlemen in the picture are Jake Skabelund and Jason Cooper. They will be the hosts for the dig. Let us hear from you if you think you will be interested in this experience.

Science Gifts Unwrapped: the Microscope

Here's a nice daydream for you. You've been given a microscope for the holidays, for your birthday, for St Swithin's Day... whatever the occasion, you've got a terrific gift on your hands. So now what do you do?

Science writer Natalie Angier put her view on the matter in this way in her excellent book, The Canon:

"Another fail-safe way to change the way you see the world is to invest in a microscope. Not one of those toy microscopes sold in most Science 'n' Discovery chain stores, which, as Tom Eisner, a professor of chemical engineering at Cornell, has observed, are unwrapped on Christmas morning and in the closet before Boxing Day... it wasn't until my daughter received a dissecting microscope as a gift, and we began using it to examine the decidus of everyday life, that I began yodelling my hallelujahs. A feather from a blue jay, a fiddlehead fern, a scraping from a branch that turned out to be the tightly honeycombed housing for a stinkbug's eggs. How much heft and depth, shadow and thistle, leap out at you when the small is given scope to strut..."

-- page 24

Almost any microscope will open up a world of wonder and amazement for you, if you give it a chance. Life on earth, after all, began with the very, very small. Much of what goes on in the world around us, and indeed passes unnoticed, is a result of processes taking place at the level so minute that human eyes require mechanical aid to see it. What is the largest and most successful class of living organism on the planet? If you said bacteria, then you're exactly right.

There are a few simple things to remember, before you even get started:

1. The microscope is only as good as its parts. By this, I mean that if you buy the inexpensive microscope with plastic optics and expect to be able to see wonderful things through it, you're probably in for a disappointment. It's not a universal law, as there are some good inexpensive 'scopes out there, but basically, you do get what you pay for. And I mean that in the nicest possible way.


2. Bells and whistles are good. You will find that the more flexibility that your microscope offers you, the more possible uses you will likely find for it. Interchangeable eyepieces and objectives, binocular / dissecting versus traditional design, multiple light sources with a rheostat, adjustable stages, compatibility with digital camera add-ons - these are just some of the things to consider. You'll want to get the most out of your microscope, so why not make it as flexible as possible?


3. Consider what you don't know. Then get a book. Two books, even. Books will give you some great ideas for basic sorts of experiments, and serve as a guide to the basic equipment that you'll need to go with your microscope.
   
   
   Here are some possible books to consider, from the shelves at the Beagle...
   
   

   
   
   • Star Levine's The Ultimate Guide to Your Microscope - colourful and well-illustrated, with lots of discussion of technique and the fundamentals of microscopy. Indispensible, especially for younger readers.
   
   
   • Richard Headstrom's Adventures with a Microscope - I'm a huge fan of Dover Books, and this is a wonderful reprint. Don't let the fact that it's almost 70 years old fool you - this is a great book, filled with lots of practical exercises and possessed of a quirky, idiosyncratic style. Headstrom also wrote Adventures with a Hand Lens, which I heartily recommend.
   
   
   • Georg Stehli's The Microscope and How to Use It - another Dover book; the discussion of microscope technology will interest anyone who likes to know about the history of science, but it is somewhat dated now. The rest of the book, however, is again full of practical, sensible suggestions for projects and explorations with a microscope.
   
   

   
   
   
   


4. Attend a class. Even audit a local university-level biology class, or look for a workshop (we've got one in the planning stages at the Beagle, watch this space for details). If you studied biology at university, or way back in high school, you'll want a refresher course.


5. Slides: making your own, buying prepared. Personally, I think it's good to do both. You can get a basic slide preparation kit from us, or put together your own, suited to your own interests and requirements.

It's your microscope: do what you want to do. The possibilities of the micro world open up just as readily as do those of the macro world with a pair of binoculars or a telescope: don't miss your chance to see all things miniature.

The Galileo Project

The International Year of Astronomy may be over but the celebrations of Galileo continue. This Sunday, January 31, at 4pm, The Friends of Chamber Music present Tafelmusik -- The Galileo Project: Music of the Spheres at the Folly Theater, 300 W 12th St., Kansas City, Mo. This concert will include NASA/Hubble Space Telescope images, live narration, and even some music by Galileo's father, the famed lutenist and music theorist Vincenzo Galilei.

In addition to the music and images, there will be a lecture beginning at 2:30 on "The Life and Inventions of Galileo," featuring facsimile copies of first edition books by Galileo courtesy of Linda Hall Library.

For more information check out http://www.chambermusic.org/Default.aspx?tabid=137

For tickets go to http://www.chambermusic.org/Default.aspx?tabid=194&CategoryID=2&List=1&SortField=ProductNumber%2cProductName&Level=1&ProductID=49