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Onyx Kitchen Backsplash

Backlit kitchen onyx slab countertop with honey onyx backsplash Fort CollinsI just finished an onyx backsplash in a kitchen with backlit slab onyx countertops. The countertops are solid honey onyx slabs with built-in LED lighting beneath them. The backsplash is 12 x 12 honey onyx tile installed on-point (diagonally).

Although onyx looks great when installed it is a very difficult stone to work with.  Onyx is made up of bands of silicon dioxide, commonly known as quartz crystals, which fuse together into layers of translucent stone. This leads to varying striations of color and transparency throughout the stone. While cutting or fabricating bullnose (rounded) edges the stone is fairly brittle and has a tendency to literally shatter like glass.  The most important tool to own while working with onyx is patience.

After letting the stone set overnight so the mortar could cure I grouted the backsplash with C-Cure brand “Macadamia” unsanded grout. Never use sanded grout with onyx or other fragile stones such as polished marble, the sand in the grout will scratch the surface of the stone. The grout will lighten as it cures and matches the base color of the stone almost perfectly. The grout lines will nearly disappear after the grout cures.

If you need an onyx installer in Fort Collins or Northern Colorado just give us a call. You may click on any of the photos below for a full-size version.

{ 14 comments… add one }
  • MARCUS July 30, 2012, 6:22 am

    Hello Roger,

    I am having some honey onyx tiles installed around my fireplace as a surround this week and I don’t want the install ruined. I know that a white thinset has to be used, but do I need to instruct my installer to seal the stone before grouting to avoid any color changes with the stone? I would greatly appreciate any suggestions you could provide. Great Job on the Onyx Backsplash. Thank you!!

    • Roger July 30, 2012, 9:30 pm

      Hi Marcus,

      You actually don’t need to use a white thinset – it’s simply normally the best option. You do not need to seal the onyx before grouting. The face of a good onyx tile is nearly identical to glass, not much will penetrate it (grout-wise).

      You may see what is called ‘framing’ after he gets finished grouting – don’t panic. :D That’s just moisture from the grout being absorbed into the sides of the tile making it look a bit darker around the edges. That will dissipate in 2-7 days, it isn’t permanent.

  • Ron March 31, 2012, 4:57 pm

    We are planning on making a 12″ by 25″ bar shelf bordered with Ironwood and would like to back light the Onyx… Does the light go beneath the tiles or do I need to run it on the sides of the tile? Also how much light would be required for the job… ie LEDS 1 strip for the length or more than one. Can florescent lights be used under the tile?

    • Roger April 1, 2012, 4:18 pm

      Hi Ron,

      If you are using onyx tiles you’ll need a substrate which is not transparent nor translucent. Placing the light source beneath the tiles will not be an option. You can place lighting along the sides of the tile and those will light them to a point. The light will diminish toward the center of the tiles utilizing that method. The amount of led’s is entirely dependent on how bright you want it – there is no standard for that, it’s a personal choice.

      Florescent lights can be used behind transparent or translucent surfaces. It is normally a better option for backlighting.

  • Clarence Cabaldi March 11, 2012, 3:18 pm

    Hi Roger, I am thinking of creating an accent wall in my bathroom by installing 3 or 4 8″x8″ onyx tiles. Can you suggest what type of tools and material I would need? Or is this too small a job for your company? I am a novice so any information would be appreciated. Thank you, Clarence………..

    • Roger March 13, 2012, 6:36 pm

      Hi Clarence,

      We do all sizes of jobs. You’ll need a good wet saw with a glass blade on it, trowel for your thinset and grouting supplies. Those are the very basics. Am I understanding you correctly – you only want to install a total of 3 or 4 tiles?

  • Gabriela January 23, 2012, 1:19 pm


    Im covering the bathroom walls with honey colored onyx, 1/2 in thick, and I want to backlight it, what kind of adhesive can I use to that? I need some kind of clear glue to hold the lights and tiles.

    I am also covering another bathroom with dark green onyx, but this thicker, 1 1/2, and it will also have LED lights in the back. What can I use for this as an adhesive?

    • Roger January 26, 2012, 8:51 pm

      Hi Gabriela,

      To backlight onyx on a wall installation it must be installed to cladding. That is a panel or mechanical fastening which allows the onyx to have space between the wall and the back of the stone. This open area is where the lights are installed. There is no ‘clear’ adhesive to use for this type of installation. There are different methods that *may* work but none have been tested long-term, none of which I’m aware anyway.

  • Vickie Feeman August 15, 2011, 1:58 pm

    I am thinking of using Onxy Fantastico for kitchen counters, but I’m concerned about the care. I was told that if we had them honed and sealed, they would not spot as easily. Do you think they would be difficult to maintain?

    • Roger August 15, 2011, 10:01 pm

      Hi Vickie,

      Any natural stone requires considerably more maintenance than ceramic or porcelain. Natural stones also have ‘layers’ or degrees of required maintenance in specific applications. Onyx is fairly brittle so it does not handle items such as skillets being dropped on it very well. It chips easily if you aren’t careful. ‘Honed’ simply means the stone surface has been ground to a flat, consistent surface.

      Properly sealed, with a very good sealer, and cleaned with the proper products (Ph neutral stone cleaners) it will last very well. It will require regular, specific maintenance, though.

  • Roxane October 4, 2009, 1:50 pm

    I love this website. The onyx back lighting idea is spectacular !
    My husband and I know that we want an onyx backspash for our kitchen. However, we were worried that amber onyx would be too soft for our countertops and instead were thinking of a granite countertop or even porcelian due to the hardness of the material. We were curious if you have seen a granite that looked great with amber onyx. If so, which granite (s) ? (Right now we were thinking of a slab of golden butterfly that is really rather orange and brown. And, we were looking at a slab of golden oak granite (brown like oak). Our cabinents are beige. We also have wood trim at the very top and a brown busy mosaic tile floor. Thanks for any advice !

    • Roger October 4, 2009, 3:53 pm

      Hi Roxanne,

      Thank you for the kind words!

      The look really depends on your particular taste. Some people lean more toward a contrasting color scheme and some toward a complimenting.

      The golden butterfly, in my opinion, would end up really orange with a honey or amber onyx backsplash. The golden oak would look good. You may also want to take a look at colombo gold, madura gold, or calypso gold granites. Any of them would compliment a honey or amber onyx backsplash.

      Hope that helps.

  • Mike September 9, 2009, 8:51 pm

    I installed 5/8 onyx backsplash and I am having problems with the grout. The onyx is golden, but when we grout it turns dirty brown. Do you have any suggestions on what to use?
    I am thinking about using clear caulk.


    • Roger September 9, 2009, 10:16 pm

      Hi Mike,

      The problem you are having is due to the light transmission through the sides of the tile. When you add grout, of any color, you will considerably diminish the amount of light entering into the individual tile. Since onyx, especially honey onyx, is highly translucent removing any of the light will mute the natural color. To maintain the color of the stone you want to allow as much light transmission as possible through the sides of the stone.

      Clear caulk is an alternative but I would not use it. It will still mute the stone’s translucence to an extent and caulk is not made, nor recommended, for that application. Think about the clear bead of silicone in a shower or bathtub. Once the airtight seal of the two materials (such as the tile and acrylic of the tub) is broken and moisture gets behind it, this leads to mold and all types of unsavory things you don’t want in your kitchen backsplash.

      The two alternatives that I have used are either a regular epoxy, the two part glue, that cures clear, or what is called “knife grade” liquid polyester. The latter can be found at a specialty art store and places such as that. It is used in casting and fabrication processes. Hope that helps.

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