Why Does Granite Stain From Weathering

How to prevent etching.

Why does granite stain from weathering.

Granite countertops stain easily. The porous granite soaks colors and dyes often resulting in stains after lots of use or exposure to some fluids or objects such as oil based cosmetics food colored drinks and metal objects. Oxidation is shown on the edge of the surface skin where iron in. Will water stain granite.

If you re not certain what caused the stain consider its size shape and location to give you clues. But substances like cooking oils that don t evaporate can cause permanent stains if they re allowed to soak into the stone. The crystals in the granite are being decomposed by hy drolysis. Granite is relatively impervious to water and is only minimally absorbent.

For example a natural stone such as marble is much more porous than granite. Etching is a dulling of the surface of the stone that may seem like a stain. Most of the time any liquid spilled on granite will remain on the surface for at least a few minutes. Chemical weathering of granite occurs when dilute carbonic acid and other acids present in rain and soil waters alter feldspar in a process called hydrolysis.

That s one of the reasons it is such a popular choice for building exteriors all over the world. Granite qualifies as impervious to water and is actually less absorbent than some solid surface plastic products. Feldspar crystals are white and will break down faster than the quartz crystals which are greyer. Feldspar gives granite a pink gray green or bluish hue while quartz affects a whitish opaque appearance.

Proper sealing and polishing of your countertops can guard against etching from acids. Since granite and other natural stone is porous liquid and stains can penetrate the surface. Granite countertops are absorbent. That being said granite is less porous than many other types of natural stone.

Granite is commonly used as building material for high rise buildings due to its ability to withstand gale force winds and rain. Deposits of granite are exposed as the softer rocks above them weather and erode. These stains may first appear as dark spots which come and go for some days but after some month they change the mineral structure of the stones and stay forever. Water is highly unlikely to cause a stain on your granite countertop.

Etching is a chemical reaction that occurs when granite is exposed to an acid such as vinegar fruit juice soda wine or ammonia. Start by determining the source of the stain. The crystals found in granite are coarsely grained and consist mainly of feldspar and quartz. Irreparable damage can also be caused by permanent humidity in combination with immigrated minerals or salts out of the subsoil or foundation.

If the granite is unsealed this liquid may soak into the granite pores. Granite itself is extremely hard and therefore weathers very slowly.