Why Do Acids Damage My Stone Countertop?

A common concern about stone countertops is how they’ll wear over time. As one of the most highly-used surfaces in your home, it just wouldn’t be economical to have something that looks crummy in just a few years! And, while durability is one of the best reasons to chose a natural stone countertop, they can be pretty high maintenance and can be more susceptible to wear and tear than synthetic materials — especially when exposed to acids.

But, stone countertops are coated in layers of sealants. How can acid get through, and why does it cause either erosion (wearing away of the stone) or etching (a dull spot in the shape of the acid spill)?

Let’s answer the second question first. Stones like limestone and marble are the most susceptible to acid erosion or etching because they have a high concentration of the mineral calcite. Calcite reacts to acids in even weak solutions and causes it to dissolve. On your countertop, this most often results in an etching, which is a noticeably dull spot where the acid has reacted to the top layer of stone. If the acid is left on long enough, the stone can degrade further and cause an indentation.

Granite is much more resistant to acid etching because it contains little to no calcite, though the stone still has natural pits and fissures that can trap acids and degrade slowly over time. Still, it shouldn’t be as big of a problem as with marble and limestone.

So, which acids should you worry about? For kitchen countertops, you should be careful about not spilling lemon juice, vinegar, wine, or cut any acidic fruits and vegetables like tomatoes and pineapples directly on the countertop. You should also be careful of common household cleaners, which can be very acidic as well. Most sealants won’t prevent etches, and those that do tend to change the finish in a way that most don’t find appealing. With that said, always use specially formulated cleaners on your countertop, always use a cutting board, and make sure you clean up any spills ASAP or they can leave an etch faster than you may think!

Although some people like etches and feel that it gives their countertop a “lived-in” look, most find them visually unappealing. For minor etches on polished marble or limestone, you can buy a specially-formulated polishing powder to remove the blemishes yourself. Be sure to follow the instructions on the package but typically, you’ll need to mix the polishing powder with water and work the mixture into the etch using a soft cloth until the shine reappears. Keep in mind that this could take several minutes, so don’t be afraid to put in some elbow grease!

For severe etches or indentations, you’ll need to call in a professional to re-polish the area or sand down the entire stone with special tools. Your countertop will then be re-sealed and re-polished until it looks as good as new.

Honed marble already has a matte surface, so it won’t show etches as easily. However, etches may still appear and cannot be removed by yourself. Since the stone isn’t polished, you can’t buff out the etch without giving your countertop a strange shiny spot that will definitely be noticable! This will also be a job for a professional.

Although finding an etch on your countertop can be distressing, don’t fret about it too much — even the most careful homeowner is bound to get at least a few over time. Thankfully, these little spots are usually easy to remove, but if you have any doubts you’ll want to contact a professional for advice for help with the restoration. Have you had any issues with etchings on your countertop? Let us know how you fixed it in the comments!

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