Sandstone Chemical Properties

Sandstone Physical Properties

Sandstone Composition

Sandstone Textures

Sandstone Chemical Properties

The chemical constitution of sandstone is the same as that of sand, the rock is thus composed essentially of quartz. The natural cementing material that binds the sand together as rock is usually composed of silica, calcium carbonate, or iron oxide. Chemically sandstone is very resistant Mono-Mineralic rock, with silica as the principal. The percentage of each constituents is as follows:

SiO2 93-94%
Iron (Fe2O3) 1.5%-1.6%
Alumina (Al2O3) 1.4 to 1.5%
Soda (Na2O) & Potash (Kro) 1.0% to 1.2%
Lime (CaO) 0.8% to 0.9%
Magnesia (MgO) 0.2 to 0.25%
Loss On Ignition (LOI) 1.0% to 1.2%

They are highly resistant to acids, alkalis and thermal impact.

Sandstone Physical Properties

The physical properties of sandstone includes following:

Color
The color varies from red, green, yellow, gray and white. The variation is result of the binding material and its percentage constituent.

Water Absorption
The capacity of water absorption is not more than 1.0%

Hardness
Lies between 6 to 7 on Moh's Scale Density 2.32 to 2.42 Kg/m3

Porosity
The porosity varies from low to very low.

Compressive Strength
Varies from 365 to 460 Kg/m2

Sandstone Composition

Sandstones are classified on the basis of the composition of their grains. Three components are considered:

Based on the percentage composition of these components, the color and the physical properties of the various varieties of sand stone varies.

Sandstone Textures

Sandstones have different surface textures, which varies according to their formation. However now a days the stones are fabricated as the desired texture and the usage. There are six main types of surfaces that are in use.

Natural
The natural surface texture is achieved by ripping along its line of cleavage to reveal the natural grain & texture. This texture gives an undulating surface with great character. The surface comes with natural clefts giving a very natural look.

Flamed
texture provides a rough surface. The roughness in the surface is a result of bursting of crystals when the stone is heated. Such a surface gives an irregular textured finish.

Polished
Polished surface texture is a reflection of polished crystals. Such texture brings out the brilliant colors and grains of natural stones. The shine on stone surface comes from polishing bricks and powders used during fabrication and not from any coating.

Honed
The honed texture is produced by grinding a surface with high grit material to a uniform specification, such that it does not produce a reflective surface. Thus honed stone colors are not as vibrant as polished stones. A smooth finish with a slight sheen is produced by using a polishing head. This surface is very smooth, but often very porous.

Bush Hammered
A pounding action that develops a textured surface. The top surface is pneumatically tooled to produce a pitted or grooved surface finish.

Sawn
Sawn surface is coarsely polished leaving a semi-smooth, regular finish. It is done by using a gang saw.

Sand Blasted
Producing a finish similar to cleft, sand blasting involves projecting a high-pressure airline coarse-grained grit, onto the top surface of the stone. It is characterized by a textured surface with a matte gloss.