This supposedly allows one to date an object by the proportion of 14-C to 12-C. Tests of Hawaiian lava flows known to be less than 200 years old have been dated up to 3 billion years old! That is, the scientists themselves do not know the effective range for 14-C.
Obviously, this works only for things which were once living.
Radiocarbon dating may only be used on organic materials.
Typically (6): The above list is not exhaustive; most organic material is suitable so long as it is of sufficient age and has not mineralised - dinosaur bones are out as they no longer have any carbon left.
When an animal dies it is taken out of the carbon cycle.
After this, the proportion of 14-C to 12-C steadily declines. 141, page 636, August 16, 1963) showed the shell from a living mollusk to be dead for 3,000 years!