Types of Surface Textures
Stones have different surface textures according to their formation, but these days stones are fabricated to give the desired surface texture. There are seven main types of surface in use.
Natural: The natural surface texture is achieved by splitting the stone along its line of cleavage to reveal the natural grain and texture, which gives an undulating surface with great character. The surface comes with natural clefts, giving a very natural look.
Honed: It is produced by grinding the surface with a high-grit material to a uniform specification, without producing a reflective finish. The colors of honed stone are not as vibrant as those of polished stone. A smooth finish with a slight sheen is produced by using a polishing head. This surface is very smooth but often very porous.
Polished: Polished surface texture is a reflection of polished crystals that bring out the brilliant colors and grains of natural stones. The shine on the stone surface comes from the polishing bricks and powders used during fabrication, not from any coating.
Flamed: It is a rough surface that is developed due to the bursting of crystals when the stone is heated. This surface gives an irregular textured finish.
Sand Blasted: Producing a finish similar to cleft, sand blasting involves projecting coarse-grained grit onto the top surface of the stone through a high-pressure air line. It is characterized by a textured surface with a matte gloss.
Sawn: A sawn surface is coarsely polished, leaving a semi-smooth, regular finish. It is produced using a gang saw.
Bush Hammered: A pounding action that develops a textured surface. The top surface is pneumatically tooled to produce a pitted or grooved surface finish.
The Hardness of Stones
The following is the well-known hardness scale for stone, which was developed in the 1800s. It helps in evaluating the strengths and weaknesses of the stone being used.
Measurement of Hardness Scale
10 Diamond
9 Corundum
8 Topaz
7 Quartz (Granite)
6 Feldspar (Granite)
5 Apatite
4 Fluorite
3 Calcite (Most Marbles)
2 Gypsum
1 Talc
The idea behind the hardness scale for stone is to measure a stone’s resistance to abrasion. When sediment and grit are harder than the surface, they will scratch and harm the stone. For example, a piece of hard plastic is about a 2.0. It will not scratch #3 Calcite (Marble). However, a piece of sand that measures 6 will scratch #3 Calcite but will not scratch #7 Quartz, which is granite. The harder the stone, the more resistant it is to abrasion. Exterior sediment that is tracked into buildings measures approximately 3.0 to 7.0.
