One intriguing thing in one of her articles caught my eye:
Cubic zirconia is a man made faceting rough with a high refractive index. When crushed and encased in a bead it gives a sparkling effect that reminds me of snow. It is sold in pieces by the carat and comes in many different colors . . .To crush it, place it between two pieces of leather or heavy fabric (not terry cloth) and hit it with a hammer. Use pieces that are smaller than a grain of rice but larger than a grain of salt.
Place the crushed cubic zirconia on a flat graphite pad. Make a medium sized opaque bead. Roll it into a cylinder shape. Encase the bead in a light colored transparent glass. Form it into a cylinder shape again. Heat the bead untill it begans to glow red. Roll the molten bead across the cubic zirconia. Return the bead to the flame and encase in clear glass.
It took me a while -- I tried many other ideas and techniques in the meantime, from millefiore to silver wire -- but eventually I got back to the CZ idea. First I bought a few small stones (faceted) from Fire Mountain, and tried embedding those in beads.
I found the smallest size, though hard to handle, were rather attractive if embedded in a dark opaque core and then encased. They would sparkle suddenly from the dark bead. I made one large bead with a core of Pig Stick purple (still the richest COE 104 purple I know of) heavily encased in clear, and it was quite nice. So without even crushing rocks, you can get some cz cut stones and try embedding them in glass.
I am not sure why this doesn't shatter the glass; I have embedded even large (6mm) diamond-cut stones inside teardrop pendants, and the pendants survived. They didn't look as good as I had hoped, but they didn't self destruct. So be bold! it seems that CZ and COE 104 glass play well together.
However, having read Rebecca's words about sparkle and snow, I had to experiment further; finally I got around to finding a source for CZ faceting rough. I bought some from The Rock Peddler, a lapidary supply house. I exchanged mail with Jeanne Ridolfi, a plain-spoken and very knowledgeable person, and ordered some "rough". "Faceting rough," btw, is the stuff that gem cutters start with when they make faceted gems: odd-shaped chunks of raw gemstone. In the case of CZ, of course, it's a synthetic stone rather than mined.
The price of CZ rough from this company varies from $8/carat for water-clear (think of a white diamond), to $10/carat for various interesting colours. You can't always order an exact carat weight because of the irregular chunks -- they may not want to split a large chunk down for you, because it might be more valuable intact. So Jeanne may call back and ask you if you will accept specific chunks of this weight and that weight. Typical colours include Champagne Peach, Amethyst, Pink Ice, etc. (Take a look at the faceted CZs in the Fire Mountain paper catalogue for an idea of the colours.) There's no minimum order for faceting rough.
By the way, there are 5 carats to a gram. There are about 30 grams to an ounce. Obviously there are 1000 grams to a kilo :-). One hundred carats of CZ would be about the size of a small cherry tomato, if it were round (it won't be).
Well, I didn't have a piece of leather. I tried heavy cotton, and the sharp CZ just tore it up. So I put the chunk of rough into my home made glass smasher and whaled on it some. It was hard to break; and this method results in a lot of wasted material (fine dust). Also, I got some contamination from the smasher (little bits of metal being chipped off the pipe cap). So this was not very satisfactory.
By washing and "panning" the frit, I managed to get most of the contamination out and tried it out. I liked the effect -- it had the sparkle of broken glass, small very sharp shards. The piece I smashed was amber in colour, but very little pigment was visible in the smaller shards. The soft glass of the bead core picked up the frit just fine.
I tried lesser and greater amounts of the cz frit. I would say that lesser is better :-) I found that a light coating was not a problem; but if I mixed a lot of cz frit in with the glass -- making a sort of slurry -- then all the beads I made with that slurry cracked after annealing. I have no idea why many little shards of CZ would have a more destructive effect than a big CZ faceted stone. Mysteries of glass, I guess.
At any rate, the sparkle was nice, and there was enough refractive (rainbow) effect that it would be attractive in, say, earrings or a focus bead for a necklace. But it was a lot of work to smash the stuff. There ought to be an easier way.
I remembered that Jeanne had said you have to be careful not to thermal-shock CZ because it will shatter. She told me a sad story about a faceting student who had just finished a nice big CZ stone intended as a gift for his wife. He took the stone off the faceting machine and tossed it into the cleaning bucket, and Tink! that was the end of that stone. His wife, apparently, was unamused :-)
I asked Jeanne how hot it would have to be to thermal-shock, and she said not very hot, less than 400F. So my next experiment was to heat up one of my chunks of faceting rough in the torch flame (very gingerly, since it's a dense material and would explode more decisively than the end of a glass rod). By the time it was warm and one corner was glowing, it had started to make alarming crackling sounds, crazing lines were forming throughout the chunk, and little splinters were flying off at the corners -- so I threw it (almost literally) into the clean cup of cold water that was waiting.
It did what a solid chunk of glass would do: fell to the bottom and sat there ticking and crackling, turning "white" with internal fracture lines but maintaining its shape. I pounded it gently with the handle end of my biggest tweezers but it was not keen on falling any further apart. A little harder pounding finally encouraged it to break up. The fragments formed by thermal shock were quite different from impact fragments: they are "gravelly" or "grain of sand" shaped. Many of the larger bits had subfractures, so that the whole thing was trying to become sand.
I drained off half the water and sat down to crush the larger chunks with hand pliers. I recommend safety glasses for this, as small fragments leap right out of the water. I kept one hand over the mouth of the cup while crushing with the pliers held in the other and the crushed material below the water surface; the palm of the hand that was shielding the cup was quickly decorated with "frosting" from below.
This method was much cleaner, but there were more unreduced large pieces.
There are more comments with the individual pictures of the few beads I have made with CZ frit so far. On the whole I would say this is a promising technique, but CZ must be used sparingly... I have fewer survivors than I have fractures, so far. Here are the hazards:
I'm currently wondering what a layer of CZ underneath a thin dichro would look like -- or CZ over (or under) silver. Write and let me know (with photos!) if you come up with something weird and wonderful.