A one of a kind gift!
Step 1: Melt Bismuth
You can buy a pound or so of bismuth pretty cheaply online. This chunk was about $20.00. Bismuth has a very low melting point so it will melt on the stove. It also has a very high surface tension so as it cools it shrinks slightly and is very easy to remove from pans and silverware. I used a cast iron skillet which worked pretty well to melt the bismuth. After melting I poured it into a coffee mug to crystallize.
Step 2: Cool and Crystallize Bismuth
It's important to heat the mug up on the stove before you pour the metal in it or you have a risk of shattering it. The bismuth needs to be in a taller container to allow the crystals to grow from the top down. Keep the stove on low heat and allow the molten bismuth to cool slowly. As it cools scrape any impurities that form off of the top. The crystals will form on the top surface and grow downward. I used an old fork to try to fish out crystals as they formed. I had to reheat and cool the bismuth down a few times in order to get a couple good crystals. Any bismuth that built up on the fork was easy to remove with pliers after. The crystals I did manage to get out looked amazing!
Step 3: Mount on Chain
Since the crystals formed on the surface the back forms perfectly flat. I had some extra chain links lying around and I was able to solder them onto the backs of the crystals. The joint might not be the strongest but it holds well as far as I could tell. From there it was as simple as putting them on a chain. It looks great and makes a fantastic, easy, ad cheap gift!