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Space and Physics

How To Make Your Own Bismuth Crystals At Home

author

Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockApr 15 2022, 11:30 UTC
Super-colorful bismuth crystal

Super-colorful bismuth crystal. Image Credit: Sebastian Janicki/Shutterstock.com

Mother Nature took eons to craft the beautiful crystals and geodes we often see in museums, but if you are interested in imitating her there’s a way that is both quicker and cheaper. You can make beautiful crystals and even geodes directly in your kitchen, with a bit of heat and a versatile little metal. Welcome to the world of bismuth crystals.  

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What Is Bismuth?

Bismuth is a naturally occurring metal with some remarkable properties. It’s the most naturally diamagnetic element: expose it to a magnetic field and it will create an internal induced magnetic field that produces a repelling force.

It also has one of the lowest thermal conductivities of any metal, a bad heat conductor in its class. It has a melting point of 271.5 °C (520.7°F), low enough to be achieved in a kitchen.

The metal has been known since antiquity and, after the discovery of radioactivity, it was considered the heaviest non-radioactive element known. But in 2003, it was discovered it was very weakly radioactive. Its half-life is over a billion times longer than the age of the Universe or 19 billion billion years.

So unless you plan to live forever, any application of bismuth is extremely safe and stable. So safe that we can guarantee most of us will have drunk it before.

What Is Bismuth Used For?

Don’t worry, people have not drunk it as a molten metal (we do not recommend that – because you’ll die). People drink it as a compound known as Bismuth subsalicylate, an antidiarrheal and active ingredient in preparations such as Pepto-Bismol and Kaopectate, which are used to treat heartburn, indigestion, upset stomach, and nausea.

In compounds, it has other medical applications as well as being used in solders and other alloys in place of lead, given their densities are roughly the same.

And then there are its artistic applications. Bismuth oxides are iridescent, reflecting light broken in its color spectrum. Bismuth crystals are popular to buy and make.

How To Make Bismuth Crystals At Home

The crystal-making process is very straightforward. You buy a bismuth ingot and melt it in a pot (one that you don’t really care for), wearing safety goggles and leather gloves. The deeper and narrower it is the better results you’ll have as you won’t expose too much of the molten metal to the air, which will oxidize it and render it useless. The air will be important only in the final step.

Once your bismuth is completely liquid, turn the heat off. Then you will have to play a waiting game. The surface of your liquid will begin to solidify, in large chunks. Underneath those chunks a crystal is forming, when you feel like it's time, pick one up with some tweezers and you will see the silvery surface become colorful as a thin layer of oxidization forms.

You can even use molds if you want to do something more creative, from funny colorful shapes to creating bismuth geodes.  

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Space and Physics
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