Sealing is the most misunderstood part of owning stone. A sealer is not a coating, it does not make stone bulletproof, and using the wrong cleaner will undo it faster than any amount of use.
What a sealer actually does
Most modern sealers are impregnators. They sit inside the pores rather than on the surface, and they slow the rate at which a liquid is absorbed. That buys you time to wipe a spill up before it stains.
They do not stop etching, they do not stop scratching, and they do not last forever. Reapplication frequency depends on use, not on the calendar.
The water test
Put a small pool of water on the surface and leave it for fifteen minutes. If the stone darkens underneath, the sealer needs renewing. If it does not, leave it alone — over-sealing leaves a hazy residue.
Test in the areas that get used, not in a corner. The sink surround will need resealing long before the far end of the island.
What to avoid
Anything acidic: vinegar, lemon, descaler, many bathroom and limescale cleaners. On marble, limestone and travertine these etch on contact.
Anything abrasive: scouring creams and pads dull a polished surface permanently. Warm water with a pH-neutral stone cleaner handles almost everything.
Takeaways
- Sealers slow absorption; they do not prevent etching or scratching.
- Use the fifteen-minute water test instead of a fixed resealing schedule.
- pH-neutral cleaner only — never acidic or abrasive products.