The necessity to quantify a natural material's homogeneity with respect to
its elemental distribution prior to chemical analysis of a given aliquot is
emphasised. The instruments and methods which are currently available are
described. Additionally, the calculation of element specific, relative homo
geneity factors, H-E and the minimum sample mass, M-5%, to achieve 5% preci
sion on a 95% confidence level is given. Especially, in the production and
certification of certified reference materials (CRMs) this characteristic i
nformation should be determined in order to provide the user with additiona
l inherent properties of the CRM, to enable more economic use of the expens
ive material and to evaluate further systematic bias of the applied analyti
cal technique.