The marble quarries of Milet and Herakleia in the Latmos mountains, western Turkey, have been surveyed archaeologically. The sites with numerous remains of unfinished architectural pieces provide information on early techniques of working stone. Samples of marble from both sites were analyzed microscopically and chemically. Marbles from Milet can be distinguished from those from Herakleia, based upon the grain size and the amounts of iron, magnesium, and strontium. -- AATA