There are advocates of the use of glauconite as a chronometer for geologic time scale studies who insist that if the geohistory of the sample in question is known in detail, one can ascertain before hand that the sample will yield a radiometric result that is accurate in the geological sense. Examples are presented indicating that while some glauconite samples may yield the correct age within their assigned analytical uncertainties when compared to high‐temperature minerals, others clearly do not and are too young by varying degrees. The outright acceptance of published results on glauconite can result in erroneous age estimates of various biostratigraphic levels and stage or epoch boundaries.