Surface processing of stone by water-jet: assessment of the minerals' luster and comparison with traditional technologies

Natural granite stones play an important role in construction and contemporary design because they are often used for cladding, flooring and generally for street decor. Luster is one of the features which are worth focussing on in order to determine where and how exactly natural stones should be used. Luster is directly related to the aesthetic features of the stone. It is not easily assessed due to the lack of economical instruments as well as standards. The objective of this study is to determine and analyze luster appearing on rough stone surface obtained using different surface finishing methods. For this purpose, a granite with a finish obtained using traditional technologies as well as a varied water-jet technique is studied. Image processing of the specimen are used to assess the luster of each mineral type in relation to the surface finishing technology. The correlations between operating parameters with luster are studied. The variations in the percentage of shiny crystals are also determined. The results of these tests indicate that water-jet technology further enhance the luster more than the competing technologies. Finally, the proposed method for the assessment of the percentage of shiny crystals on a rough stone surface has proven effective.