Monday, October 11, 2010

My First Silver Ingot

This here is my first cast silver ingot!!! Oh, what a rush! It required the catching of breath when finished and carried with it the WOW feeling I remembered from sky diving. The process begins with a small baggie of silver granules - imagine silver Nerds candy. These silver pieces are first poured into the white plastic pipe, as in the top right corner of this picture. When the crucible is ready, i.e. "sweetened" with Borax powder and heated with the torch; the silver is poured into the crucible using the plastic pipe - like a decanter. The crucible is shown to the left of the plastic pipe - made from a ceramic material, it must first be heated with Borax until there is a glassy finish within. Next to my pinkie-finger you can see the steel mold that the ingot is cast in. Using thick, heat resistant gloves I first lightly oil the inside of the mold, and then clamp the two pieces of the mold so they are perfectly aligned. Both the crucible and the mold are heated at the same time with a torch that has a large "rose bud" tip, until a little smoke from the oil can be seen rising from the mold. The silver granules are then added to the crucible and the melting process begins. This takes about 10-12 minutes, until the silver first turns red hot (like charcoals ready for grilling) and then mixes together like mercury. Once the silver is all moving together, it is then poured quickly and evenly into the mold. The mold is then quickly opened, and the silver ingot quenched in water. ~ I suppose the excitement of this cannot be written well in words, but it certainly is exciting!
In other news, I had a good Saturday this past weekend. A couple friends from class and I went to a small Gem Show in Vista, CA just outside of Carlsbad. At one table we met a man named Robert who deal in gems out of Riverside, CA. He expressed to us that his business was more of a hobby, and so he's not out to make much money. Because of this, his prices for gems were more than reasonable, and his collection was very nice. My friend Jeff bought an UNTREATED blue topaz crystal for just $35!!! (GIA testing still to be done). The reason this was such a deal to those not in the know, is this....most Blue Topaz on the market has been heat treated to achieve that color. Your best luck of finding untreated blue topaz is if bought directly from the mine, but once the crystal passes through a few hands, treatment is more than possible, and close to guaranteed. The reason why blue topaz is one of the least expensive gemstones on the market is because there is a lot of it, and its treatment is fairly inexpensive. This all being said, Jeff's blue topaz still will need to be identified by the GIA as untreated and it is really just a specimen stone - not quite gem quality, but perhaps a tiny stone could be cut from it. If a stone were cut from it, and came with proper documentation proving its lack of treatment, it would be worth quite a bit more.
I bought one stone for myself, a 1.7ct Andalusite...about a 7x5mm oval cut stone with a light brown transparent body color, and good pleochroism of reddish orange & green seen all over the stone. = Pleochroism means that the stone has more that one color to be seen and usually the differing colors are seen from different angles. You may know of Tanzanite, which is a pleochroic gem. The best Tanzanite color is a purplish blue, similar to a fine blue sapphire. From some angles, the tanzanite will look more purple, other angles more blue, and sometimes, it can show colors of grey and light violet. How Andalusite is different, is that from the face-up view of the stone, all of its colors (greens, reds, browns, golds) can be seen reflecting at once!! I chose from a small selection of Andalusite. There were larger stones, but they didn't show as much color, and then there were stones that with my trusty Kassoy loupe in hand, I could see were more included (by flaws, but I hate that word). Now, I wish I had bought more of the stones. Andalusite is a rare stone in gem quality, but because it's not a desirable stone in the market, it's rarity does not make it expensive. It sold for $15 per carat, and I got it for $20. If it were not so rare in gem quality, I do believe that Andalusite could be a very marketable stone. It ranks around 6.5 to 7 on Mohs scale of Hardness, which puts it up there near Quartz. And with it's pleochroic phenomenon, it could certainly be desired, if consumers were aware of it. It's entirely possible that a new source of Andalusite could be found, and that it could flood into the market in the future. Because of this, it may be a stone I continue to study and collect, and eventually work into my fine jewelry designs. Ah, the future we will see!!!!!


  1. wow paul, that's beautiful!! so cool...

  2. aren't some people really into chiastolite? (that pretty andalusite variety with the cross in the middle). or is not that worth it in terms of gems? so cool to hear you speak of Mohs scale of hardness and pleochroism! I've never seen pleochroism in a hand specimen of anything, but have seen it plenty of times under the microscope (with hornblende and such). so what sort of classes are you taking now? anything in optical mineralogy?

  3. Yes, Chiastolite, otherwise known more simply as Cross Stone - very cool. And yeah, it's popular among collectors, but not with the same rarity as gem quality andalusite. Neither of them are expensive, because the market doesn't make them so. I am sure you have seen Pleochroism in a's not totally uncommon. Go check out a Tanzanite in a jewelry store. Most of what little stores would have, or Zales for instance, would be a light lavender Tanzanite, but if you tlook at it from the side it might appear grey, or even colorless.