MassMeasure that is also known as the gram-atom.
Defined as the mass in grams of 1 Mole of pure substance. For example,
1 AtomGram of Carbon 12 will be 12 Grams of pure Carbon 12. 2 AtomGrams
of the same substance will be 24 Grams of it. This is an unusual unit in
that it is essentially 1 Mole of 'stuff' measured in grams, so that the
actual value (i.e. mass) depends on the type of substance.