Gemological usage of marble-calcite formations

The aim of the study is to use marble fragments with calcite minerals, which are abundantly observed in our country, as ornamental stones different from their current usage areas. Calcite minerals were obtained from Kerimler neighborhood of Toroslar district of Mersin province, and marble fragments were obtained from marble processing companies. Three types of marbles suitable for coloring, white, beige and gray, were selected from marble processing companies. Among these three marble types, to maximize the dye absorption by increasing the porosity and finding the ideal condition, in which the coloring will be permanent, experiments were carried out by heating the marble for these three types of marbles. Furthermore, experiments were carried out by heating at 5 different temperatures (at 100 -150-200-250-300 0C), 5 different times (30 minutes - 1 hour - 1.5 hours - 1.5 hours - 2 hours - 2.5 hours) and keeping them waiting in 5 different dye solutions (food coloring, copper sulfate, fabric dye, ink, methylene blue). As a result of one week of waiting, it was understood that the best results for all marbles were given in copper sulphate solution, and that there was an effective dyeing at all temperatures and times. It was found that fabric and food coloring was less effective than the others. If a protective coating was not applied, it lost its color completely in a long time. It was observed that white and beige marbles stained darker at low temperatures in methylene blue staining and at high temperatures in ink staining. However, at the end of one year, except for copper sulphate and methylene blue, the color of the others faded. Therefore, it was revealed that a protective coating such as epoxy should be applied to make these paints permanent. Apart from these experiments, a permanent coloring was achieved in white crystallized marble, which was kept in a solution of natural iron oxide prepared with linseed oil for 4 months and reheated. In addition, it was observed that the gray marble, which was subjected to heat treatment in a preheated oven, was kept in a solution made with blue food coloring, white vinegar and hot water for 21 days. After this step, it changed into a purple color in which the dye was absorbed to the inner parts. In order to show their usability as gemstone, jewelry applications were made on polished marble which gained yellow color by being kept in iron oxide - linseed solution, polished marble after gaining green color in copper sulfate, and ink dyed shaped marble whose color was preserved by coating with epoxy. Keywords: Dyeing, Gemology, Gemstone, Marble Supervisor: Assist. Prof. Dr. Meltem GÜRBÜZ, Mersin University, Department of Gemology, Mers