The results of research drilling are extremely important while stone deposits are being graded and evaluated. It has been shown that good quality core and proper interpretation of drilling results contribute a lot to the results of research works as well as to working with and making full use of stone deposit. Results of research drilling need much more time and attention considering that they are one of the most expensive types of research. They ease the evaluation of stone deposits according to decorative, tecnological and geological criteria. The elements that can determine the integrity and consistency of the stone mass are especially important. For a detailed assessment of the consistency, it is important to register any kind of defects that might cause breaking of the core, stone block or tablet during sawing, grinding and polishing, or which might cause it after stone elements and tablets had been installed. On the contrary, insufficient, incomplete and incorrect usage of results and information gained by research drilling, most often leads to excessive money spending and proper directing of exploatation gets much harder. Without proper data, over time, the real image of the stone material from the drill site is fading from memory. That often leads towards wrong directing and irrational exploatation. With uneccessary drilling into tectonic zones the production of blocks is slowed down and the expenses of exploatation gets higher.