Home » Granite, Limestone and Marble - Part I: Structural and Chemical Effects on Water Absorption
Each class of sealer has advantages and disadvantages. Notably, film formers often result in a high gloss, plastic-like surface that inhibits the gas exchange between substrate and the atmosphere ("breathing"). Heavy films are also prone to delamination ("peeling") and/or scratches. Penetrates offer a more natural look and are not subject to mechanical failure. However, they may not offer the same level of protection, which may be important in industrial settings. Further, some products may have different degrees of protection depending on the substrate. For example, silanes (sometimes called "silane coupling agents") work well with feldspathic (i.e., granite) and concrete materials, but not calcareous ones (marble, limestone).2 Aluminum stearates work well with limestone, but not bricks.3The mechanism and bonding of alkoxysilanes has been studied in detail and significant differences in performance between limestone and sandstone have been observed.4
Siliceous stones are defined by the Marble Institute of America as "granite, quartz-based stone, serpentine, slate and soapstone." They are durable and easy to maintain under normal conditions of use. Calcareous stones include limestone, marble, onyx, and travertine. These stones are durable, but more sensitive to acids and strong alkaline compounds. More specifically, granites are defined by the American Society for Testing and Materials (ASTM) Designation C119-02b as a "visibly granular, igneous rock generally ranging in color from pink to light or dark gray and consisting mostly of quartz and feldspars accompanied by one or more dark minerals." Generally, most granites5 are composed of approximately equal amounts of quartz (silicon dioxide; SiO2), feldspars6, and plagioclase. ASTM C119-02b defines limestone as a rock of "sedimentary origin composed principally of calcium carbonate (the mineral calcite; CaCO3), the double carbonate of calcium and magnesium (the mineral dolomite), or some combination of these two minerals." It also says that stone capable of taking a polish, such as marble or travertine, is also included in this category. Interestingly, concrete is sometimes referred to as "calcium carbonate," even though this is incorrect - although cement is derived from limestone, hardened concrete is bonded by calcium silicate hydrates.7
For this issue of Stone World magazine we talk to some of the leading suppliers of Stone from India, as they discuss what is new. Also, we feature articles from top water filtration companies in the industry to talk about how to run a safe, clean and efficient shop!
For this issue of Contemporary Stone & Tile Design we focus on the current quartz trends and the use of quartz in a modern farmhouse. Also, learn about how natural stone is used to blend nature and exterior architecture!