How To Make Bismuth Crystals On The Stove

No one really needs a whole bunch of bismuth crystals. So why would you make a bunch of it?

Because it looks cool. Obviously.

Bismuth is non-toxic, at least, it is not bio accumulative so you would need to consume a whole lot at one time to have issue. The bismuth compound bismuth subsalicylate is the active ingredient in Pepto Bismol. It is the most highly diamagnetic element known, and is slightly radioactive with a half life of approximately 19,000,000,000,000,000,000 years. The low melting point of 520 degrees fahrenheit makes it a simple task to melt on a kitchen stove.

In case the video does not play for you (I know Instructables has issues playing embedded videos on mobile) the process I use is quite simple:

1. Melt the bismuth in a stainless steel sauce pan. The smaller the pan the better because it will give you a deeper pool of bismuth for the crystals to grow in.

2. Once molten, turn off the heat and skim the oxide and contaminant layer off the surface with a fork.

3. Wait for the surface to begin to solidify, crystals will be forming below as this happens.

4. Gently move the solid rafts that have formed on the surface to keep the crystals on the underside from freezing to the bottom of the pan.

5. When the rafts start to hit other things below the surface as you move them it’s time to pull them out and see the result.

6. The crystals formed can be remelted to form new crystals by repeating the process over again if the results weren’t satisfactory the first time around.

For best results I recommend using at least 4 or 5 pounds of bismuth for the surface crystallization method demonstrated in the above video. The deeper the pool of bismuth is in the pan the better, because the crystals will have extra room to grow before they touch the bottom. The more you use the more impressive your results will be.

Some of you that are familiar with other forms of crystal formation may be thinking that I give bad advice when I state that you can move the crystals as they grow. Usual crystal growth requires a very still solution with no movement, and a very slow cool down period. I did quite a lot of experimenting with this method and found that bismuth does not behave quite the same way. Once the crystals have begun forming it does not seem to matter if they are moved so long as they remain submerged. Further structured growth happens regardless of disturbance once there is a point to nucleate from.

You may also notice that I was not wearing gloves for a portion of the video, that was foolish of me. I was wearing eye protection the entire time. Leather gloves (not synthetic!) and lab goggles should always be worn in case of splashes or spills.

The bismuth I used for the project was 99.99% pure in ingot form which I purchased from eBay.

Have fun and stay safe!

Source: Instructables