The 1908 Hammacher Schlemmer catalog shown above included a nice selection of sharpening stones. The prices are fun to check out - an 8" Arkansas stone, for example, is listed for $9.80 (well over $300 in 2024 dollars, by the way). Interestingly enough, a boxed version of an Arkansas stone of this size is listed at half the cost. Therein lies a story.
Arkansas stones are finicky. While nowadays many people are sharpening with diamond stones and artificial water stones, the hardness of a translucent Arkansas stone -and the edge it gives in sharpening - is still considered spectacular, especially among carvers.
Quarrying the very hard Novaculite, the technical name of Arkansas stones, has always been tricky. I've written a lot in the past about the grading of the stones, hard, soft, black, translucent, and so on, but I've never really written about the actual difficulty of extracting the stuff from the ground. Most of the quarries in the world for Novaculite are in Arkansas and owned by Norton Abrasives. By most, I mean that very hard quartz is found pretty much everywhere, but for commercial quantities the main source is Arkansas.
Folks want a perfect Arkansas stone, but the stone itself is incredibly brittle and hard. The way you get it out of the ground is by drilling holes; filling the holes with explosives; blowing off chunks of rock; and then taking a look at what you have. The first problem is the explosives. The quarries use black powder, not anything modern, because black powder produces a slower explosion. This means that the stones don't get smashed to smithereens - good of itself and also because there is less stress on the stone that can cause internal fractures. The next problem: you have a bunch of stones that are heavy and need to be sliced up. If you slice them up efficiently, you get a lot of nice sharpening stones. If you slice them up the wrong way, you waste a lot of material. You can't really tell for sure until after you slice them up. I don't know what's happening at Norton since they moved production to Mexico. Is there any finishing work still done in Arkansas? Guessing what's inside a stone before you actually cut it up is a skill. You may have a block of beautiful Novaculite, but when you slice it open you may find tiny cracks in the material. These flaws can even be significant enough to cause the stone to fall apart. In most cases they are simply a visual flaw that will not effect functionality for next million years. By this time, of course, you have spent a lot of time figuring out your yield and cutting things up. So at best you're annoyed.
For the past century- plus, Norton has solved some of the problem by taking stones that have flaws in them, cutting away the flaw and making a smaller stone - slipstones and all sorts of smaller stones. But in the past, if they had a stone that was perfect except for a flaw or partial fracture (it's not really a crack because it's not going to open), what they would do is glue down the stone into a box flaw down so that you didn't see it. And in the Norton cataloging system, if a stone is a perfect translucent or black Arkansas stone (they didn't make the distinction until recently), it would be known as an HB X where X is the size, with the most common designation being HB8. (You'll occasionally see HB6s, HB7s, and HB4's but it HB8 is the most popular size). Glued down in a wooden box, the stone is known as an HM8 (or seven or six depending on the size). Now to be fair, the chances of you wearing through an HB8, or an HM8, in a lifetime is pretty small. The stones do dish but very slowly, and if you use the entire surface of the stone it's a very minor non-issue. Some carvers end up resurfacing their stones with diamond powder every once in a while, but again we're talking about something that wears very slowly.
This is why the boxed stone is half the cost of an unboxed stone. You can only use one side.
People want perfection so the HMs are a tough sell. This isn't a new marketing ploy.
I was once told that going out to the quarry and blowing things up starts out costing about ten grand. That's a lot of stones, but the market is small. I've also been told, that you can't quarry Novaculite in the winter because the cold temperature lowers your yield. I have been recently told by Norton that the reason they don't have any HB8s currently is that they have to go to the quarry and find some material and lately they've been unlucky. That's certainly possible. It's also possible that they can't justify the cost to just willy-nilly blow up a bunch of rock. Some other sharpening stone suppliers don't seem to have any really first-rate translucent material either. I know in the past Norton has quarried material and sold it to other companies, so I worry that Norton has concluded that mining translucent Novaculite is no longer economically viable for a large corporation.
The other thing that concerns me is the loss of skill over time. We were recently sent a stone by the company that was labeled as HB8 that was full of cracks and flaws and was the wrong color. This in itself is pretty interesting because I don't really know what this stone is. It might be an elusive Ruby Red Washita, which I have been looking for for years, but I am not sure. It might’ve been mislabeled at the factory, and they realized it was mislabeled, and they sent it to me because I knew I would be interested. Nobody is telling me anything.
from the top: chipped HB8, Actual HB8, Mislabeled HB8 Close up of mislabeled stone, showing fractures
N. B. We happen to have in stock two HB8 stones that were damaged in transit. We'll be putting them on the website in a couple of days at a discount.
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10/18/2024 Stephen
Very interesting. Great post. Thanks for the info. I use the arkansas stones and never switched because they work great. I understand that they are slower, but unless you have a chipped or damaged edge touchups don't take much time.
10/18/2024 Rudye
Interesting read about Arkansas stones. Do you have any more detailed information about flattening these stones? How do they do it at the factory? I have several natural stones (maybe Arkansas's, but I'm not sure). I realized that they are decidedly non-flat. I've tried several ideas for flattening, but they are all very slow. Currently, I'm using Silicon Carbide grit on glass, but at some point the glass isn't flat anymore.
Rudye,
Currently the stones are sawed apart using diamond stones and I don't think they are touched up after that.
In the old days they are cut apart using abrasives and wire and then flattened on modified lapping machines that looked like primitive Blanchard grinders
10/18/2024 Michael Fischer
This was a great read, awesome information. thanks for sharing.
10/19/2024 JimC.
Fascinating read. I have a hard Arkansas stone and a very small translucent that was given to me by Caterpillar dealer here in town. I really like the edge from them and find it amazing to be able to raise a bur on the translucent.I have been fabricating boxes of sort to house all my oil stones after watching how Bill Carter uses a hardwood end grain ramp, flushed on the ends of stones to allow using the full stone more readily. So far so good, seems worthwhile. Some day when I'm flush with spare discretionary play funds I going to invest in a eight inch black if they are even still available.
10/19/2024 JimC.
After my comment I looked at stones on your page and saw you sell a 8x3 translucent boxed. My question is can these be removed box safelyto make my own box without damaging stone?
Jim,
We actually don't have any 8x3 stones at all. When we did they were not HM's so they were not glued down. The one web post I found about someone who removed a stone from an MB8 box managed to leave a lot of stone fragments in the box.
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Currently the stones are sawed apart using diamond stones and I don't think they are touched up after that.
In the old days they are cut apart using abrasives and wire and then flattened on modified lapping machines that looked like primitive Blanchard grinders
We actually don't have any 8x3 stones at all. When we did they were not HM's so they were not glued down. The one web post I found about someone who removed a stone from an MB8 box managed to leave a lot of stone fragments in the box.