Natural Radioactivity


Demonstration Requirements: The best (read: most cost effective) demonstration tool for natural radiation is the Victoreen CDV-700 Geiger Counter. There are a lot of other models on the market including other Victoreen counters like the model CDV-720. However, the CDV-700 was specially made to react to lower levels of radiation. Such as you might find with gemstones and mineral specimens. The others were built to detect far higher levels and do not read as well to the lower levels of minerals and gemstones. As some of you might remember, during the 1960's we were all waiting for some fool either in Washington, D.C. or Moscow to push the button on a nuclear holocaust. So all of these Geiger counters were made during that time so we could keep them in our homes. Just so we would know when the radiation levels were safe enough for all of us to come out and join the next Stone Age. So the CDV-700s you find will be a relict of the Cold War. The one in the picture at left was purchase about a year ago and was fresh out of the box. Never been opened for 30 years. Cost about $100.00 on eBay in case anyone is interested in owning one. But this Geiger counter, a piece of pitchblende, and a lead lined film pouch is all you need.

Teachers Demonstrations: A safe way to demonstrate natural radiation in a classroom is to use a lead film pouch that is sold in local camera stores. The one's that are sold to carry film through an airport X-ray machine. By leaving your pitchblende sample inside the lead pouch you can actually control which direction the radiation is pointed and keep everyone in the classroom safe. You can use the wand of your Geiger counter to pass over the open end of the pouch and demonstrate the natural radiation of pitchblende. Then, you can simply reseal the pouch and no one is in harm's way. Natural pitchblende is available on eBay from several dealers. Just be careful about how you ship and handle the material.

WARNING: This radioactive specimen of pitchblende was purchased on eBay and arrived without any special packaging. While this specimen can be controlled by just a few wraps of aluminum foil, it was not wrapped during shipping. I have purchased some cesium crystals on eBay that require special handling and lead containers. These arrived properly contained and packaged so that no radiation was leaking during shipping. (Which I am sure my mail carrier appreciated) Be very careful about buying radioactive specimens on eBay or anywhere else. Some of these guys either don't know what they are selling, or are not informing people of the potential risks and special handling requirements of their specimens. BE CAREFUL.

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Robert James FGA, GG.....YourGemologist

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