Water Repellent Silicone (synthetic oils): Generic synthetic oils which tend to leach from surfaces and migrate. Of limited use due to the tendency of attracting dust and limited life expectancy. There are many types but you can generally rely upon the fact that you get what you pay for. This type also darkens many types of stone surfaces.
Siliconates: Water based silicone derivative useful for light colored, porous stone. Inexpensive. This type should not be used on dark colored stone or important surfaces. Any residues not absorbed will disfigure surface with a salt-like precipitate. May be useful for some limestone and concrete surfaces. Only water beads. Re-coating is not possible due to the fact that it repels itself.
Damp Mopping: A damp mop is capable of picking up microscopic abrasive soils and potential staining agents. Damp mopping is recommended for most smooth surfaces on a regular basis. Best done after sweeping or vacuum.
Siloxanes: These are state of the art quality, specifically in long life and high vapor transmission. Moderate cost. Used primarily for exterior stone surfaces including marble, granite, limestone, slate and cement based building products as well. Suitable for clay pavers and roofing tiles. Highly recommended for most surfaces exposed to weather and/or high humidity. Does not darken most surfaces. Solvent based is normal. There are some new emulsions available which can comply with VOC restrictions.
Stearates: This is the cheap water repellent sold to consumers in chain stores and hardware stores for wood, concrete, masonry etc.. Performance is poor and short lived. Not recommended for most building stone.
Oil Repellents: These are proprietary products which repel oil as well as water and other liquids. There are a number of these specialized products designed for use on stone surfaces. Most are fluoroplymer-based but there are some other types (rather exotic)
Drying Oils: These are the original natural polymers. They include Tung , Linseed and Soy. These oils become solid as they dry and are of potential use for sealing stone surfaces. They are organic and, consequently, they are relatively sensitive to aging and will yellow with age but are useful in some situations.
Waxes: Waxes may be natural or synthetic and include Carnuaba, paraffin, montan, beeswax etc. They are typically formulated into paste waxes or emulsions for sealing purposes. Their effect is less than permanent and typically they are re-applied on a regular basis.
Silicates: These are mineral glasses which fill up pores and increase the density of porous surfaces. Very useful for restoration of stone which is under chemical attack or exterior weathering as it can repair lost minerals and provide protection from further degeneration. They are specialized materials which require expertise to formulate and apply for predictable results.
Waxes: This category is primarily paste waxes composed of paraffin, beeswax, and some synthetics. They can be very effective for maintaining a shine and prevention of stains. Some professional products contain dyes or pigments which can be useful in bringing out or maintaining the color of red, black and green stones (primarily for furniture). Carnuaba based waxes may be suitable for some low abrasive surfaces and is used in specialty maintenance products.
Coatings: Coatings are usually acrylics, urethanes, epoxies, varnishes, lacquers etc. and have limited use on natural stone however there are some typical uses of these film forming polymers. The most common coating is the janitorial type floor finish that is applied to floors to maintain a physical barrier which isolates the stone surface from abrasion. These coatings are considered temporary or sacrificial and are used primarily because the coating is easier to restore when it gets damaged than the stone surface would be without the coating. In general, film-forming coating are avoided on natural stone if possible.
Soaps: Soap is potentially useful in a number of categories because of the residue that soaps tend to leave behind. The residue can be utilized as a sealer in some situations or may be intentionally built up and used as a natural paste wax or dressing. Soaps are very valuable for maintaining stone surfaces and in most cases are 100% reversible. Soap residues “dress” or nourish a stone, preventing the stone from drying out and being overly absorbent.