Coloured marbles from different sources can be distinguished by the experienced eye without any further analyses. In the case of white marbles the macroscopic characteristics are limited and a series of analytical methods have to be applied to discriminate and assign marbles to their corresponding sources.
Overlap of datafields
During the last years marble provenance analysis was confronted with the problem that one single method like stables isotope analysis is not sufficient in discriminating between many different marble sources.
In most cases we therefore use a multivariate approach in marble discrimination.
Sample size and surface contamination
Another problem is in many cases the very small sample size and the surface contamination of these small chips.