Pink quartzite
Pink quartzite , also Flamenco or Lencois quartzite , is the trade name of a fine-grain quartzite from Brazil , which is quarried near Lencois in the state of Bahia .
Origin and composition
Like all quartzites, pink quartzite is a converted, quartz-rich natural stone. Heat and pressure transformed this into a metamorphic rock, thus becoming a new rock with completely different technical properties. Pink quartzite consists of up to 99 percent quartz. The red to yellow color results either from the iron minerals hematite (red, reddish) or limonite (yellow, brownish). Depending on the occurrence and distribution of the minerals , individual layers are colored differently.
Technical characteristics and use
Pink quartzite as a natural stone has a high resistance to scratches, even surgical steel leaves no traces. The main application is decorative interior design, such as B. Table tops. The relatively unfavorable pore radius distribution has proven to be a disadvantage. This allows color-changing substances to penetrate the stone very easily. There is another effect, especially when laying steps and floor slabs with cement mortar: depending on the alkalinity of the mortar water, the chemical reaction with the coloring substances can cause irreversible discoloration. The resulting “ picture frame effect” comes about through the penetration of mortar water, for example, and via the grout in the edge zones of the individual panels. For this reason, a strongly buffered system should be used, because such a picture can arise even when using reaction resin mortars, mortars based on plastic. These cases of damage have meant that hardly any stonemasons use this stone for floors or stairs. Even when this quartzite is used as a kitchen worktop, the use of so-called impregnating agents based on silane - siloxane is unsatisfactory.
These facts show that abrasion hardness should not be confused with usability.
Optical variants
This quartzite comes on the market with different decorations. If it is gated against the bearing - that is, perpendicular or at an angle to the layering - it shows a striped decoration; with the bearing, i.e. cut parallel to the layers, it has a cloudy appearance. Due to changes in the distribution of the coloring minerals, the pink quartzite often shows weak, broad veins.
literature
- Karlfried Fuchs: Natural stones from all over the world, discover, determine, use . S. 147, Callwey, Munich 1997.