Among the various ores of the Lavreotiki subsoil more important are galenite (PbS) and cerussite (PB.C.O3), because they contain argentiferous lead. Occasionally these ores, which are usually composite and include non-argentiferous elements, from pure deposits that, however, are rare and limited. The mineral wealth of the region mainly consists of composite deposits. The exploitation of the argentiferous deposits in Lavreotiki seems to have commenced during the Protohelledic II period, that is around 2,500 B.C.. Until the end of the sixth century B.C. the miners used to extract only the purely argentiferous deposits and those rich in argentiferous lead, while all the rest deposits were not mined, due to the technical problems in their smelting. Around the late sixth or the early fifth century B.C., the metallurgists of Lavreotiki discovered-or learned from others- that the composite argentiferous ores could be turned to recoverable ones, if they were granulated, then mill grinded and finally washed with running water, so that all their non-argentiferous components to be removed. This method was indeed very effective, however it stumbed at the fact that Lavreotiki was a dry land. Thus, to handle the shortage of water, the metallurgists invented the ore washing-table: a device in which the water would drift away the lightweight non-argentiferous granules of the grinded ore and would leave clean the heavier argentiferous lead particles. Then, through a circulation system of canals and basins, the water would be self-cleaned, due to the subsidence, from all the components it had drifted along during its course and would return to its starting point pure and appropriate for use for the next cleansing route. The adoption of the washing-table solved the problem of water shortage and in fact multiplied the exploitable mineral wealth of Lavreotiki. Soon after it led to the maximization of the mining works and as a result to the provision of the Athenian State with an important and steady income from the exploitation of the Lavreotic silver. This considerable financial support contributed to the establishment of the newly born Democracy and the repellence of the Persians and fertilized as well the earth of Athens for its great political and intellectual flourishing, fruit of which was the so-called Golden Age of Greek civilization.