ABSTRACT
Granite blocks from Capão Bonito was used at a sawing enterprise to obtain slabs and the final product had streaks on the Quartz mineral and this defect motivated this study. The resulting slabs were also of a lighter color than the usual dark red that is one of the most appreciated feature of this mineral, and this is a cause of great concern as this factor may sharply influence the commercialization of the end product. Two hypothesis were considered for this study as follows: the first one related to possible modifications in the quartz mineral from a determined area of the deposit, and a second alternative related to the operational conditions during the industrialization phase due to the sawing procedure adopted at the plant. Mineralogical and microhardness analyses of the quartz from many samples provided useful information, which were compared with identical analysis performed with other samples that did not present this problem. The purpose of the quartz mineralogical analysis is to determine the technological characteristics of those crystals. The complete absence of quality control procedures for cutting tools (sawing blades and grit) as well as gang saw operational conditions at the mining enterprise prevented more conclusive analysis. Capão Bonito granite comes from the same area where this problem occurred and is exported in great scale as well as consumed in the domestic market, and the recommended solution is to improve tooling quality control and the operational conditions of the sawing equipment.
