The other method is “Relative Dating” which gives an order of events without giving an exact age (1): typically artefact typology or the study of the sequence of the evolution of fossils.
AMS counts the quantity of 14C in a sample rather than waiting for the isotope to decay; this also means greater accuracy readings for older dates.
The 14C isotope is constantly formed in the upper atmosphere thanks to the effects of cosmic rays on nitrogen-14 atoms.
In 1979, Desmond Clark said of the method “we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation” (3).
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.
Stone and metal cannot be dated but pottery may be dated through surviving residue such as food particles or paint that uses organic material (8).