An isotopic data base of delta¹³C and delta¹⁸O analysis of 528 samples collected from 39 classical Greek and Roman quarries of Turkey, Greece, Italy, and Tunisia has been accumulated. The discriminative possibilities of the database vary from quarry to quarry. Most quarries have a distinctive pattern for either or both variables, but some have more than one grouping. The data also overlap for many quarries preventing a unique provenance assignment. If the alternatives are known so that the total pool of possible sources is reduced, the database can then discriminate and assign a provenance for most classical marble artifacts.