These radioactive elements in minerals and ores originally found in the environment are commonly known as NORM – naturally occurring radioactive material. Some NORM materials require radiation control ...

The abundance of naturally occurring fullerenes in carbon materials (for example, coal, rocks, interstellar media and even dinosaur eggs 10) therefore suggests a possible route for SWNTs to form ...

Naturally occurring radioactive materials are present in its crust ... This differs for each radioelement, ranging from fractions of a second to billions of years. For example, the half-life of Iodine ...