Recently I’ve bought a little specimen of Autunite from China. My sample is 20mm in lenght, 15mm width and 6mm thick with nice green lamellar crystals. I’ve bought it from a chinese seller because I couldn’t find an equally nice sample from Europe.
I’ve received it after 30 days from the order and immediately I’ve painted it with transparent acrylic pain to avoid contamination with tiny powder that could be lost during handling.
I’ve tested it with my SV500 geiger counter that measure beta+gamma at contact in the range of 20-25mRad/h and 3-5mRad/h of gamma’s only. This is an highly active sample as expected. It’s radiation emission doesn’t travel too far in air and at just 10cm from the sample, just my scintillation probe could measure it. I’ve made a gamma spectrum of it’s emission with a NaI(Ti) scintillator.
As you can see it’s easy to detect it’s thorium and radium content. There are also decay products like Pb214. Bi214 is a characteristic decay product of Ra226. Take a look at the Ra226 decay chart below
In conclusion this specimen is not a fake made in China, is just a nice high activity sample.