Originally Posted by hednic
Did you actually do lapidary work on rough?
You bet I did ! And it was a real treat, I can tell you!
You could tell they were not using the most delicate methods of mining the stuff at that time, as there was some of the sort of fracturing that comes with dynamite. But when all that you normally see are small cabs of the stuff, it came as a revelation to me just how large a slab you could get, once you sliced the stuff up with a diamond saw.
Not that it should have been that big of a surprise though. As I understand, there are places in Russia where they have big structural columns of the stuff.
Getting a good final polish was difficult though. You'd take it down to really fine sandpaper, things would look great, but when you took the final step of polishing it with polishing powder on a leather buff, then you'd suddenly get "orange peeling" that was a reflection of the individual piece's relative grain structure.
I suspect there's a trick to avoiding that, but I never quite figured it out. As I understand, the material is akin to marble, in that sometimes, if you go to marble supply rooms, you'll see huge slabs of material for marble countertops that have streaks of lapis in it.
If I had the chance to buy rough again, I'd pay closer attention to the nature of exterior of the chunks. A smoother fracture surface probably reflects a finer grain structure and a higher grade of material.
But yes : Just having the opportunity to see big deep blue raw chunks of the stuff, as big as your fist or bigger, with the pyrites sparkling on the surface...it was nice alright.