Radioactivity in minerals are caused by the inclusion of naturally-occurring radioactive elements in the mineral's composition.
The degree of radioactivity is dependent on the concentration and isotope present in the mineral.
For the most part, minerals that contain potassium (K), uranium (U), and thorium (Th) are radioactive.
Because mineral specimens containing radioactive elements are naturally occurring substances and are collected in small quantities, there are no official licensing requirements for their possession and storage.
When considering plans to store radioactive minerals, there are three categories of potential radiation hazard that have to be addressed:
* External exposure to alpha, beta and gamma radiation
* Contamination from radioactive particulate material;
* Radon gas emanation which is the major concern in a storage environment.
Specimens should be stored as far away from areas of human activity as possible, such as against an outside wall, or at the back of a drawer or case. Be aware of the human activity and use of the space on the other side of the wall or case. The use of lead shielding is not recommended for most collections, especially those with fewer than 100 radioactive specimens. It should be remembered that lead has its own well-documented health hazards.
To minimize inhalation and ingestion of dust, wear washable or disposable plastic gloves, keep areas free of dust by using a damp wipe, and wash hands thoroughly after working with or near mineral specimens.
The level of hazardness of a specimen depends on the size, number of crystals, concentration and type of radioactivity.
To set things in perpective here a some radiation levels μSv/h (=micro Sievert per hour)
During 1 airplane flight: 40-50 μSv/h
X-ray picture: 10-100 μSv/h
Background radiation (in Holland/Belgium): 1500-2500 μSv/h (per year)