This is a kind of surface finish that is ideal for lava stone products that are polished, buffed or also previously bush-hammered.
Historically carried out by hand with mallet and chisel, it consists of etching grooves, thin or wide, shallow or deep and separated, with greater or less irregularity, and is obtained by using diamond discs or a wide range of tools with variable profiles (single or multiple creasing hammers). The end results on Etna Basalt are rather diversified because of its response to light, above all when it is very radiant, and the effectiveness in certain applications (external paving), depends a lot on the working specification. In grooving, most of the final effect depends strongly on the depth of the grooves, on the “precision”, if this is how it can be defined, with which these grooves are carried out and the uniformity of appearance presented by the material.
Our Basalt even with its great homogeneity, is much appraised for its etching and, as a matter of fact, this type of surface working is little used, perhaps due to the particular micro-hardness of the surface to be treated. Also the contours of the individual crystals constitute another reason that limits the immediacy and precise identification of the kind of working done that is called grooving except in the case of shiny surfaces.