Does the Sedgwick Museum of Earth Sciences have any radioactive gemstones? This was the question we were asked by Kanta Kiyomoto, a Year 8 student at Cambridge International School. Kanta is studying various forms and sources of radiation for his Silver CREST Award and wondered if we could help out with some radioactive gems.
Dr Ben Winpenny, our Collections Assistant in Mineralogy and Petrology, suggested that Kanta looked at some of the rocks and minerals on display in the Museum and offered the use of one of the sensitive radiation meters from the Earth Sciences Department. Kanta couldn’t use his cloud chamber because it involves isopropyl alcohol and dry ice, things that we don’t want in contact with our collection.
Kanta took the time to write about his visit to the Museum and his meeting with Dr Winpenny:
“I had the opportunity to visit the Sedgwick Museum for my cloud chamber project. I have been working on my project about cloud chambers and radiation for the Crest Club. I was able to detect some radiation coming from the atmosphere and the cosmic background radiation. Afterwards I tested it with putting potato, banana, and granite in it. I also researched about radiation before going to the museum, and surveyed different types of them, for example, Alpha-ray and Beta-ray.
“At the Sedgwick Museum, I met Dr Ben Winpenny, who has researched volcanoes. I got the chance to use the Geiger counter to observe radiation from various different specimens of rock including some of the oldest rocks on Earth, which are nearly 4 billion years old. This was very interesting because I could perceive audibly what I had tried visually identifying with my cloud chamber. It was also intriguing, using the Geiger counter, how in some areas, the sounds could be heard constantly while in others, rarely. Therefore, I could conclude that some areas of the specimens differ from others in amounts of radiation. By discussing radioactivity and that on an atomic scale with Dr Winpenny, I was able to deepen my understanding of radiation and learn more fascinating things such as how the charges of the radiation make the cloud chamber work. I also got top tips for my next experiment such as to try low sodium salts as a radiation-emitter instead of regular table salt, as the sodium in the salt is replaced by potassium, which could be more radioactive.
“It was a very special experience for me in the museum and I highly recommend discovering the museum and feeling the fantastic magic of old rocks. I would also like to thank Dr Winpenny and other staff for arranging this amazing opportunity for me!”
So does the Museum have any radioactive gemstones? As Kanta found out, there are some rocks on display that contain a slightly radioactive mineral called zircon, but not radioactive enough in this case to be dangerous. Gems are just minerals that have been chosen by humans for their beauty and durability. The Museum has many beautiful minerals on display, but these particular zircons are much more impressive for their extreme age than their beauty.
Nicola Skipper, Education Coordinator, Sedgwick Museum of Earth Sciences