NATURAL STONE

Natural stone is a geographical list of stone used for decorative purposes in construction and monumental sculpture; currently or historically produced in various countries. In additionhardstone carving uses many types of gemstones.

The dimension stone industry classifies stone based on appearance and hardness as either "granite", "marble" or "slate".

The granite of the dimension-stone industry along with truly granitic rock also includes gneiss, gabbro, anorthosite and even some sedimentary rocks.

Uses for granite include architectural stone (construction, flooring, cladding, counter tops, curbing, etc.), raw block and monument stone for the funerary trade.

Sandstones/ Arenites:

Sandstone (sometimes known as arenite) is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and pink, white. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions.

Some sandstones are resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material. However, some that have been used in the past, such as the Collyhurst sandstone used in North West England, have been found less resistant, necessitating repair and replacement in older buildings.[1] Because of the hardness of the individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which to make grindstones, for sharpening blades and other implements. Non-friable sandstone can be used to make grindstones for grinding grain, e.g., gritstone.

Rock formations that are primarily composed of sandstone usually allow percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Fine-grained aquifers, such as sandstones, are more apt to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity.

Slates:

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay orvolcanic ash through low-grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering. When expertly "cut" by striking with a specialized tool in the quarry, many slates will form smooth flat sheets of stone which have long been used for roofing and floor tiles and other purposes. Slate is frequently grey in color, especially when seen in masse covering roofs. However, slate occurs in a variety of colors even from a single locality; for example, slate from North Wales can be found in many shades of grey, from pale to dark, and may also be purple, green or cyan. Slate is not to be confused with shale, from which it may be formed, or schist. Ninety percent of Europe's natural slate used for roofing originates from Spain.[1]

The word "slate" is also used for some objects made from slate. It may mean a single roofing slate, or a writing slate, traditionally a small piece of slate, often framed in wood, used with chalk as a notepad or noticeboard etc., and especially for recording charges in pubs and inns. The phrase "clean slate" or "blank slate" comes from this use.

Quartzite:

Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of iron oxide (Fe2O3). Other colors, such as yellow and orange, are due to other mineral impurities.

When sandstone is metamorphosed to quartzite, the individual quartz grains recrystallize along with the former cementing material to form an interlocking mosaic of quartz crystals. Most or all of the original texture and sedimentary structures of the sandstone are erased by themetamorphism. Minor amounts of former cementing materials, iron oxide, carbonate and clay, often migrate during recrystallization and metamorphosis. This causes streaks and lenses to form within the quartzite.

Orthoquartzite is a very pure quartz sandstone composed of usually well rounded quartz grains cemented by silica. Orthoquartzite is often 99% SiO2 with only very minor amounts of iron oxide and trace resistant minerals such as zircon, rutile and magnetite. Although few fossils are normally present, the original texture and sedimentary structures are preserved. The term is often misused, and should be used for only tightly-cemented metamorphic quartzites, not quartz-cemented quartz arenites. The typical distinction between the two (since each is a gradation into the other) is a proper quartzite is so highly cemented, diagentically altered, and metamorphosed that it will fracture and break across grain boundaries, not around them.

Quartzite is very resistant to chemical weathering and often forms ridges and resistant hilltops. The nearly pure silica content of the rock provides little to form soil from and therefore the quartzite ridges are often bare or covered only with a very thin layer of soil and little vegetation.

Important recommendations:

It is very important to use the specific glues for these products. Amado Salvador advice to use MAXIFLEX of Mapei. Never you can stick the natural stones directly over the plaster or plaster cast only if you use before PRIMER G of Mapei.

The way to collocate these products is smooth down very well the surface and make a double pasted. And you should clean before the stones with the product PH-ZERO of Fila and waterproof the with PRW-200.

FINISHINGS:

To clean them: PH-ZERO of Fila

Wet finish: HYDROREP of Fila

Natural effect: FILAWET of Fila

Natural effect trying to do darker matt colour: STONEPLUS of Fila

Arenites trying to do darker: FILATONEUP of Fila

Arenites natural finish: HP-98 of Fila

Quartzite natural finish: HP-98 of Fila

Quartzite wet effect: FILAWET of Fila