Countertop was installed when before we moved in. It has a solid black appearance, when wiping with stone cleaner, it will be shiny but will dry to a matte finish. Also stains do not appear while wet, but after drying the white stains around faucet show back up.

The surface gets water stains very easily (dark and also some white stains that are easy to clean off) so looking to reseal, but would like to make sure I know what material the countertop is made of. I also can't seem to get rid of the white stains around faucet.

We have the same countertop in our bathroom and kitchen. In the kitchen white marks appear on the countertop after placing pots and pans on the countertop. The countertop is a little rough to the touch.

What material is my countertop made of and what would be good to clean it, remove stains, and help prevent new stains?

Edit: Went back and looked at the real estate listing and it stated the countertops were black honed granite.

Bathroom Countertop

Stains by faucet

Chip in kitchen

  • Looks Corian-ish, but there are Lots of competitors: en.wikipedia.org/wiki/Corian Apr 14, 2020 at 1:33
  • Just to be certain, the surface is not smooth and flat, but kinda wavy bumpy? The swirls in the close up of the chip look like the trait of quartz. But I have not seen a textured quartz, just natural stone. So it has my curiosity up....
    – Jack
    Apr 14, 2020 at 2:54
  • Those swirls in the chip photo are from a cup that was sitting there before I took the photo. Apr 14, 2020 at 5:14
  • the edge texture looks like sedamentary rock, so slate. but I can't say for sure that it's not artificial.
    – Jasen
    Apr 14, 2020 at 5:31
  • Soapstone came to mind reading the question - but I'm not convinced from the pictures that it's right. If that, mineral oil is the standard approach in laboratories. Whiter when dry, blacker when wet (with water or oil - if you get enough oil soaked in it will stay blacker even when "dry") - often has green veining that shows up more obviously when oiling it. Oiling best done right before you go on vacation so it can sit for a while.
    – Ecnerwal
    Apr 14, 2020 at 12:36

1 Answer 1


It is going to hard to tell precisely what type of surface you have. Too many man made look a likes out there.

But to guess, and that is all it will be, that it is a flamed surface granite. I have seen it used in lieu of natural cleft slate which has a great look, but terrible for counter tops. Granite could be sealed, but it does not take it very well, it is just really dense. If it is Quartz, then typically that is man made and does not need to be sealed. The resins bonding the quartz together provides that function.

I have seen, when sealer is applied too heavily and not wiped off well enough, that it will turn white from moisture, otherwise where untreated stone or other material will not. I would consider using a stripper of some sort for your sealer you are using, let it set and see if the white goes away, if you can get it down to bare stone again.

The area around the faucets is my clue as to what is going on, since those tight spaces are hard to access for getting excess sealer up.

As a mention, if it is Corian, it definitely does not need sealer. Nevamar is a Corian competitor, same thing. Silestone and Ceasarstone among many others, are quartz providers. So if you get a chance to look in your records, if you can find them when they installed, will give you and us a better idea on how to proceed.

And yet another mention, about the chip on the corner, there are epoxies specific for these types of tops, as well as colorants to make that chip disappear. If you got a stone top installer over for a visit, they could fix that for you in a jiff. Besides tell you what the material is that you have...

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