This means that marble is much softer and will scratch easier than quartzite.
Acid vs marble.
This black crust is primarily composed of gypsum a mineral that forms from the reaction between calcite water and sulfuric acid.
Stone surface material may be lost all over or only in spots that are more reactive.
The hardness of marble vs.
Marble has a moh s hardness rating of about 3 while quartzite has a rating of approximately 7.
Being composed of calcium carbonate marble will react in contact with many acids neutralizing the acid.
Marble is often crushed and used for acid neutralization in streams lakes and soils.
Marble and quartzite can be finished in a variety of ways.
In exposed areas of buildings and statues we see roughened surfaces removal of material and loss of carved details.
Quartzite is quite different.
Applications choose a commercial cleaner containing phosphoric acid and dilute it with water if instructed by the manufacturer.
For example while you can use phosphoric acid on ceramic porcelain and composite surfaces you should never attempt to use it on natural marble onyx granite or limestone.
It is one of the most effective acid neutralization materials.
Finish options for marble and quartzite.
However sheltered areas on limestone and marble buildings and monuments show blackened crusts that have spalled peeled off in some places revealing crumbling stone beneath.
This acid etching can only be removed by professionally resurfacing and rehoning the stone.
Particularly on older concrete slabs exposed to the elements the variable porosity of the slab allows the stain to penetrate to different depths creating natural areas of light and dark staining.
However concrete acid stain possesses the unique property of creating a marble like effect without any additional staining techniques.
It is used for acid neutralization in the chemical industry as well.