Near as I can tell, there is some kind of demand in the marketplace for all of the elements from 1 through 92, with the exceptions of Pm, At, and Rn, I suppose. It is hard to gauge the trade in actinides since precious little gets outside the realm of government regulatory frameworks. Clearly there is demand for certain isotopes of Th, U, and Pu. But the nuclear regulatory people keep a tight reign on that stuff.
I remember a pottery class I took some years back in a nearby town. I was snooping through the pottery stockroom looking for glazes and what did I find? I found a sizeable quantity of Thorium nitrate. These hapless middle-aged, post-hippy era, meadow muffin starving artisans running the co-op clearly had no idea that they had an actinide a nuclear-age artifact in their midst. Obviously, it had been secured for colored glaze applications. I warned them about it but was met with the cow-in-the-headlights-look. I call it the “bovine stare”. So, I brought a GM survey meter the next week and opened up the jar with a few of them standing there. As the clicks ramped up from the beta’s and as I switched the attenuation to keep the needle on scale, I thought I heard the unmistakeable faint slapping sound of multiple sphincters slamming shut.
The first question was “Would I like to have it?”. Pppffffttttt! “Hell no!” says I. Nuclear cooties. Jesus H. Crimony!! I did a careful survey with the GM counter and found that the surrounding area was clean. The material (early 1960’s vintage by the looks of the label) had hardly been used, so I was confident that contamination was not too bad, if indeed there was any. There may have been alpha emitters but this counter wouldn’t pick them up. I gave some names of hazardous waste vendors and a stern warning not to drop it or spill it. That’s the last I heard of it.
I remember a seminar in grad school when a visiting rock star from ETH gave an organic seminar detailing the use of Li-6 in NMR studies. The fellow lamented in his fastidious German/Swiss accent that it was difficult to get Li-6. He also said that for a time much of the refined Lithium in the market place was depleted of Li-6. It would be interesting to hear someone comment on the accuracy of this.
Lamentations on Chemistry 
Funny that you found Th nitrate in a pottery studio, but I don’t think I would call it a nuclear artifact… People have been using Th compounds for a long time. Wasn’t thoria (an oxide) used as an incandescing material in gas lamps in the 19th century?
When I was writing this I was thinking of thorium in the nuclear fuel cycle. You’re right of course about the use of thoria. A website on gas lighting says that Welsbach patented a thoria/rare earth mantle in 1885 http://www.1911encyclopedia.org/Lighting .
What was funny was that a group of persons who made a bit of a show of wholesomeness would have such a thing in their midst.
Yeah, I agree on that point. I laugh especially at crunchy granola types (though I tend towards that sometimes) with dyed hair who go out of their way to use environmentally friendly or non-irritating substances everywhere else in their lives.