However, only trinitite from a nuclear explosion will contain certain neutron activation products which are not found in naturally radioactive ores and minerals.

The highest background radiation in an inhabited area is found in Ramsar, primarily due to naturally radioactive limestone used as a building material.

Ekanite is an uncommon mineral notable primarily as being among the very few gemstones that are naturally radioactive.

Uranium mill tailings: naturally radioactive residue from the processing of uranium ore.

Shales however, are naturally radioactive due to potassium isotopes in clays, and adsorbed uranium and thorium.

Two of them are naturally radioactive, and three are expected to decay but have not been experimentally confirmed to do so.

In the last few years, the E.P.A. began to expand its program to control hazards from radium and other naturally radioactive elements but with mixed results.

Much of the heat is created by decay of naturally radioactive elements.

And each of us receives about 300 millirems of radiation each year just from living on Long Island's sandy soil, with its naturally radioactive elements.

"It is a very small volume, and the radioactive material that is in there is naturally radioactive."