In our 30+ years as a natural stone supplier, we’re still surprised by how often etching and staining get mixed up. Today we will dispel this myth with a simple breakdown of the differences between the two processes. We want you to have everything you need to know about your stone and how to look after it.
What is Etching?
Etching is a chemical reaction whereby acidic substances (citrus, vinegar, wine, some cleaning sprays) react with the calcium carbonate in calcareous stones. It shows up dull or lighter than the surrounding surface, not darker, because it’s corroding the finish itself. Calcareous stones are the most reactive with acids and therefore prone to etching.
Is Etching Necessarily a Negative?
We would argue that etching only means damage if you want a stone that will look the same as when you first got it. There is beauty in the patina that forms over time, reflecting daily rhythms of the people that use the stone.
Arguments for Etching
- It’s purely cosmetic. Etching is a shallow surface reaction, it does not weaken your stone or shorten its life.
- It’s just a finish issue. A high-gloss polish on a reactive stone like marble will make signs of wear appear very noticeable. A new etch on a honed, leathered or already-matte surface just blends in. Selecting your finish is important.
- It’s often fixable. Unlike a deep stain, light etching can be buffed or honed out professionally.
Prone to Etching
Marble‘s mostly calcite, so lemon, wine, or vinegar will dull a polished surface over time. Limestone reacts just as readily, sometimes more. Travertine, a porous cousin of limestone, shares that same vulnerability. Dolomite reacts more slowly to acid.
Less Prone to Etching
Granite won’t etch from normal kitchen acids since it’s quartz/feldspar-based rather than calcite-based. True quartzite won’t etch at all. Slate is also low-risk for etching since it’s a clay/mica-based metamorphic stone rather than a carbonate one.
What is Staining?
Staining is an absorption process where liquid soaks into the stone’s natural surface. When liquid or oil is pigmented, a discolouration may stay behind after the water evaporates. Staining shows up darker than the surrounding stone, which is the visual opposite of etching.
Common culprits are wine, coffee, tea, oils, and cosmetics.
Prone to Staining
Travertine and limestone are the most porous stones we carry, so they soak up spills fastest. Marble handles moisture a little better, but it’s still porous enough to stain, especially once polished.
Less Prone to Staining
Granite and quartzite are naturally dense, so staining is rarely an issue. Bluestone, slate and rhyolite sit somewhere in the middle, but a simple seal keeps them easy to clean.
Resistant to Both Staining and Etching
Porcelain (including SNB’s INFINITY and FONDOVALLE ranges) is manufactured, not quarried, and fired at extremely high temperatures. It’s essentially non-porous and chemically inert, so it resists both etching and staining
What Can Sealing Do?
Sealing won’t stop etching, but it’s genuinely effective against staining. We recommend sealants to clients because treated stone is easier to clean and keeps looking good for longer. The more porous a stone is, the more it can soak up, and that’s exactly what sealing is there to fix.
Travertine and limestone are the most porous stones we carry, so they get the most benefit from sealing before use. Marble handles moisture better, but it’s still worth sealing, especially if it’s polished, to keep it looking its best. Bluestone is just as easy to protect. Sealing all sides before laying keeps that natural colour true and stops discolouration from soluble salts. Granite and quartzite are naturally dense, so once they’re sealed, staining is barely a concern. Slate and rhyolite sit somewhere in the middle. A simple seal on riven or textured finishes keeps them easy to clean and looks sharp for years.
Can You Remove an Etch or a Stain?
Most of the time, yes. The fix depends on which one you’re dealing with, so work that out first. If the mark is dull or lighter than the stone around it, it’s an etch. If it’s darker, it’s a stain.
Removing an Etch
An etch is damage to the finish, so cleaning won’t shift it. A light etch on polished marble can often be buffed out with a marble polishing powder made for the job. Deeper etching, or a large area, needs a stone professional to hone the surface back and re-polish it.
Honed and leathered finishes hide etching far better than polished ones, which is worth thinking about before you choose.
Removing a Stain
A stain sits inside the stone, so cleaning the surface won’t reach it. Fresh stains can often be pulled back out with a poultice (a clay-like paste that draws the liquid back to the surface), then the area is resealed.
Oil stains and drink stains need different poultice mixes, so match it to what was spilled. Always test on a hidden spot first.
If you’re not sure what you’re looking at, send us a photo and we’ll help you work it out.
Stone Care Products
- SNB’s Stain Proof Premium Impregnating Sealer is permanent, invisible and fully breathable, protecting treated stone against water and oil-based staining, salt efflorescence, graffiti and freeze-thaw damage.
- Stain Proof Colour Enhancing Sealer does the same job while also giving porous surfaces deep, long-lasting colour enhancement.
- Stain Proof 40SK Consolidator & Water Repellent goes a step further for softer, more porous stones like limestone and sandstone, helping to consolidate and strengthen friable surfaces while repelling water.
Choosing the Right Stone for How You Live
Selecting the stone type that best suits you really matters. We know it can be daunting, so we’re always happy to help you understand what you’re buying and how to look after it.
