Finishes of natural stone
What we mainly appreciate in the stones is their colour, their veining and their grain. Processing of stones can vary our perception of the material, by considerably increasing or diminishing the relation between the three characteristics, so modifying the visual impact of the material. Therefore, one stone can acquire completely different aesthetic-perceptive characteristics, depending on the processing, the veining composition and the chromatic combination. Finishes can be machine- and/or hand-made. There are various finishes of stone slabs and they give different aesthetic results.
Main finishes of natural stone
Scraped (when the stone becomes shiny). Marble, stone and granite polishing gives the surface an extra-ordinary reflective power and enhances its colour.
Scraped (with sandpaper, without polishing). Honing is an intermediate phase of the polishing process and tends to tone down colour. Honing makes the surface perfectly flat, eliminates imperfections and makes the slab bright – yet less than polishing.
Historical impact process (blowtorch treatment after cutting or splitting), flaming gives the slabs an uneven, soft and porous aspect to the sight as well as to the touch. Flaming is done on stones and granites and makes the material anti-slip and suitable for exteriors. This process is also done by flushing water on the stone, to enhance the surface colour and make the material much more resistant to atmospheric agents.
Also called patina or glaze – obtained through brushing on a polished surface. Aging makes the stone pleasant to the touch and it is also called “leather finishing”. This finishing gives value to the stone’s natural beauty and enhances its colour, giving the stone a “vintage” look.
Historical impact process (the stone is hammered to give a regular rough surface) Bush-hammering (also “hammering”) is mainly done on granites. The stone acquires a rustic aspect and is used as anti-slip or as coating for exteriors. Bush-hammering tends to enhance the grain, making it similar to the natural grain.
The surface is eroded by flushing the stone surface with sand and air, enhancing the details. The surface is rough to the touch, and flat. Sanded floorings are ‘anti-slip and they are suitable for exteriors.
Brushing makes the surface irregular, yet without pores. It is suitable for kitchens (stains on worktables and on irregular floors go unnoticed) and it is often completed with flaming, sanding and acid treatments, which make the material easier to clean.
Or “diamond surface” – finish is done on stones, marbles and granites. It is obtained from the mechanical cut: the surface remains as it was when cut. In the picture, the streaked or sanded finish obtained with grinding machine and, on the side, the natural surface of the stone.
Typical impact process, once done with hammer and chisel; nowadays specific machinery is used, operating with pressure on the splitting lines of the stone block: the stone is cut into two with a sharp blow and the two halves remain rough.