Stone refers to non-living and solid materials that are naturally composed of the community and strength of one or more types of minerals in the earth’s crust .
Stones are generally divided into three categories :
1_ Sedimentary rocks: Materials that gradually flow through rivers to seas and lakes over time are affected by the pressure exerted by the weight of the water.Over time, these materials are compressed and deposited on top of each other and sedimentary rocks are formed.
Sedimentary rocks are divided into 4 categories :
Silica (destructive) sediments such as mudstones, cuts, conglomerates and sandstones
Biochemical sediments that are composed of organic materials such as limestones, coal, oil shale and phosphate
Sediments that are chemical and include evaporite and ferrous rocks such as travertine and rock salt
Azores such as pyroclastic deposits (fine deposits), clastic vulcania (flow deposits), hydroclastic deposits, autoclastic deposits and epichlastic deposits
2_ Igneous rocks: When molten rock (magma or lava) cools and solidifies, igneous rocks are formed.
Igneous rocks can be divided into 2 categories :
External igneous rocks such as basalt, rhyolite, andesite, trachyte and volcanic tuff
Internal igneous rocks such as granite, gabbro, diorite.
3- Metamorphic rocks: Metamorphic rocks are created when existing rocks are exposed to high heat, high pressure ، Hot fluids rich in minerals or a combination of these factors .
Metamorphic rocks are divided into 2 categories:
- It has orientation such as phyllite, schist and gneiss
- Unoriented like marble, quartzite and hornfels
Each of the stones can be used in suitable places :
1_ Staircase and flooring :
For stairs and flooring, a stone that is very hard and has high impact wear resistance, and due to exposure to pollution, it must have low porosity. Quartzite and gneiss can be mentioned among the stones suitable for floors and stairs.
2_ Interior walls of the building :
The stone used for the wall should have a beautiful appearance and a polished surface. In addition, its porosity is low so that it is not damaged by washing with detergents and its resistance does not decrease, such as quartzite stone.
3_ Building diagram :
Durable and resistant stones are used for the facade of the building so that they are not damaged by various environmental factors . Granite and travertine are suitable for use in facade construction.
4_ Wall and foundation :
For the wall and foundation, stones that are porous and have high layering and solubility should not be used. The use of hard stones with high compressive strength and specific weight is suitable for this work, like most sandstones and dolomitic limestones.
5_ Roof cover :
Special roof stones should be light weight، They are non-porous and impenetrable and have high bending resistance, and they must also be divided into thin and flat layers, such as chlorite and micaschist schists.
6_ Decoration :
For interior decorations such as fireplace walls, columns, door and window frames, and stones that have a good color and appearance, and in addition to high durability, They have good bending and tensile strength, they are suitable like travertine stone.
Methods of stone processing :
In order to physically change the surface of the stone and achieve beauty and special effects, it is necessary on their surface ، Payments are made according to the space where the stone is to be used.
For example :
Travertine stones, due to having holes on their surface, are first filled using mastic and stone chips ، Then they are used for construction works because if they have holes, their maintenance cost increases.
Stone polishing or finishing is a part of the stone production process that has different types :
Ax stone processing method :
For stones that are supposed to be used on the floors of buildings or on stairs ، It is customary to ax the surface of the stone with tools that are placed on the stone in the positions of nails ، This causes the lysis of the stone surface to decrease and causes friction.
Axing is mostly done on travertine stones and some stones such as Limestone . By performing this operation, the stone looks whiter and brighter.
Palish or Saab :
It is the most common stone processing model that makes the stone more polished and gives a special softness to the stone . The surface of each stone before the sub should be completely healthy, but if it has a fracture or crack ، The back of the stone is glued with a mesh network and a material known as resin or mesh glue to fill the pores in the stone and make the stone strong and integrated.
Saab operation is done after filling the pores in the stone .The stone is placed inside the Saab device and depending on the material of the stone and its hardness, the Saab operation is performed on the stone and makes the stone find its desired gloss and transparency
In the polishing process of some stones, such as black granite stone after the grinding stage ، The action of dye-sabbing is also performed to color the surface and make the stone look more black.
Flimming :
At this stage, the stone is burned both manually and by special machines. This operation creates roughness and roughness on the stone.
Leather film :
This stage is also similar in appearance to helium, with the difference that the surface of the stone does not have the roughness of the helium. It is mostly used for stones that are supposed to be used in walls.
Hound :
At this stage, in addition to polishing the surface of the stone, with a special method that is processed, it matts the surface of the stone and gives it a special beauty.
The surface of the stone is also softened and smoothed, and this type of finishing is mostly used for decorative purposes.
Cut :
At this stage, stone plaques are cut parallel and shallowly from different and desired angles by tool devices.This finish can be used in decoration and decorative spaces.
Scratch :
In this finish, the surface of the stone finds a soft, linear and regular texture. Due to giving special beauty to the environment, this finish can be used in the exterior facades and interior walls of buildings.
Sand blast :
One of the finishes in which the exit stone has a very beautiful appearance is sandblasting. In this finish, the surface of the stone is changed by the sandblasting machine and takes on a texture similar to the finish of flim.This payment is mostly used in large size plates and slabs.
Resin work :
Resin (mastic) method is done to fill stone holes with the aim of strengthening and increasing quality . Polyester resins are in solid and semi-solid liquid states.
Resins (mastics) are found both transparently and in color modes . Today, specialized mastic is used for each stone in stone quarries, such as marble mastic (HA), marble-specific mastic (translucent).
Semi-transparent mastic for marble and marble
In addition to the reasonable price, this resin does not need special equipment and can be drawn on the stone with a spatula .The stone needs to be completely dry before contact with the resin.
The drying operation is done by both the furnace and the sun or by exposing it to heat. Epoxy resin can be used for better processing on stone.
Epoxy resin is more resistant to sunlight .This means that it does not turn yellow in front of the sunlight and with its lower concentration and less setting time, it has more permeability in the stone and this makes the work of Zarin easier .Types of stones and their processing methods
