Each method of nuclear age determination involves a different sequence
of sample preparation. Wood, peat, charcoal, bones, or shells are
cleaned for carbon-14 dating in order to remove every trace of possible
contamination by modern carbon as well as extraneous old carbon. Rocks
are crushed and ground, minerals are separated according to what is
needed in any particular study, and the desired elements are extracted
and separated by chemical procedures. Often there may be several
different ways of doing the same thing; different laboratories use
different procedures. In every case, however, long and complicated
procedures must be followed before results are obtained from which an
age can be calculated. There is no such thing as a black box into which
you can throw a rock and read its age on a dial!
Of all the elements that are part of the useful parent-daughter systems,
only potassium is common enough to be analyzed by conventional chemical
techniques. All the other elements, especially the radiogenic ones, are
present in such small quantities that special processes had to be
developed to measure them. The most valuable and generally used process
is called ISOTOPE DILUTION.