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Radiation in gemstones

I’m trying to gather information on eudialyte, which is said to be mildly radioactive. I’ve read that it poses no health concerns as long as the stone is no more than 5 cts. But cabs offered online are way bigger than that. What is the current thinking on this?

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There is a table for estimated eudialyte radioactivity per size of specimen on Webmineral. Holding a 10 gram (50 ct) sphere of eudialyte for 1 hour will expose you to 0.02 mRem. Holding a 100 gram (500 ct) sphere for 1 hour, 0.24 mRem. Holding a 1000 gram (5000 carat) sphere for 1 hour, 2.4 mRem. As we note in our IGS eudialyte entry, the estimated annual exposure to radiation in the U.S. is 360 mRem. I hope this information helps.

IGS Admin

Hi Pedro: Thanks so much for the info and links.

So, hypothetically, it looks like a large cab of @40 mm/100 gm would expose you to @ 0.24 mRem if you wore it for one hour. If you wore it every day for 8 hours for 365 days, it would expose you to 700.80 mRem.

According to the latest info from the Nuclear Regulatory Commission the average radiation dose for Americans is 0.62 rem or 620 mRem per year.

So altogether, in the above scenario, you’d be exposed to 1320.80 mRem in a year. That’s more than twice the average, but apparently still not a concern.
According to the South Carolina Dept of Health and Environmental Control no harmful effects are seen at doses less than 5,000 mRem (5 Rem) in a year. They add: “In fact, effects seen when humans are exposed to 100,000 millirem (100 Rem) over a short time period are temporary and reversible. It takes a short- term dose of greater than 500,000 millirem (500 Rem) to cause a fatality.”

So it appears that eudialyte cabs are not a threat to your health, even if you wore them every day. Although, according to Addison Rice’s article on the subject, such gems should be stored separately from other gems and monitored for radon gas buildup.

Does all this sound right to you?

Thanks again!

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It does seem it would need to be an absolutely enormous eudialyte held close at hand for unusually long periods of time to be a concern. As for radon gas, that’s something that accumulates in an area over time whether the stone is held in hand or not, so it would be wise to monitor that, especially if you’re storing a significant quantity of the material.

IGS Admin

Thanks Pedro!

I’d also recommend storing it in a lead lined container if you have one just to be paranoid