I stuck some of my white glass tiles on a board and grouted one section with white, and one with gray. I'm sorry I didn't keep it so I could show you, but yes, the gray grout really deadened them for me...made them look like gray tiles, too. I went with bright white?

Here's mine. White grout, very thin spacing.

I think that looks very nice, ck. I agree that you a counter with visual activity, matching reducing the contrast of the tile/ grout is a good idea. My tiles are white, so I guess in choosing white grout I basically did the same thing. So I guess I can't really compare my experience , since the OP has non white tiles,.

We had a glass penny-round detail in a shower we did last year. I used dark gray grout because I wanted the contrast with the subway tiles that made up the rest of the shower (and I don't love white grout in showers). I really regretted it, it killed the rounds.

I think a grout the color of your tile would look very nice and subtle, sometimes contrast can be too much...

Thanks to all who responded for all this - very helpful and exactly the answer I was looking for.

raenjapan I'm sorry your tile didn't turn out the way you hoped but thank you very much for the input. sixtyohno and ck^2 both your backsplashes are very pretty and I think this helps quite a bit. sixty - is your tile from Lowes? Looks very similar in color to ours.

I'll go ahead and look for grout that matches exactly - I assume we'll still use white thinset even though the tiles are opaque. Hopefully that'll help keep the color clean and light.

I wonder if I did the grout a little deeper than normal if that would also help preserve some luminosity because then light could enter the side of the tile? I'll have to do some experiments. Thanks again!!

I would try to find a grout the same color in a shade darker than the glass tile. It would blend, but the tile would stand out, not the grout.

Don't forget to use a good tile sealant. So much tile work is ruined because people don't spend the time/money to seal the tile with a good sealant.

Do they have anything clear for grouting glass tiles? Some kind of silicone compound would look nice. I have no idea if it would work.

Hmm that's a thought, Rose. I know there are epoxy grouts and I was thinking to use one of those but I've read they're a pain to work with.

I'd be afraid that with something clear, you'd see the lines in the thinset from behind....

A couple of things; one, any grout, regardless of its color, will block light from shining through the sides of your glass tile. This is what causes a reduction in light reflection (through or from glass tile). Our glass tile installed, did/does look different from the ungrouted sample board we'd brought home when choosing our backsplash, and really looks different from the mesh mounted sheets of tile. It's the nature of the beast so to speak. :)

The second thing I want to point out; we used white grout with our glass tile (clear and matte glass tile, back-painted white). We don't seal it all the time. In fact, it hasn't been sealed since it was installed (Aqua Mix Gold; a water-based sealer??) and it still looks new (and white).

Right over the vent/trim piece on the back of our range, we would sometimes end up with grease deposits during oven use (vented out of the trim piece). These deposits are easily removed (dissolved?). I spray some alcohol-water spray on the backsplash, let it sit a minute or two, and wipe with a paper-towel or microfiber. Occasionally I'll give it a second spray. Since we started sliding a piece of foil between the trim piece and the backsplash when we use the oven, it's cut down on deposits. If we do happen to end up with any stubborn "stains" (again right over the trim piece, and usually after prolonged, high heat roasting), I'll spray with Dawn Power Dissolving Gel, let sit, and give a scrub with my blue scrub sponge.

FYI; the newer TEC XT grout is even more stain resistant than their original grout(s), but we didn't use it in our kitchen (not available then?).

cat_mom makes a good point about grout of any color blocking light entering from the sides of the tiles and eliminating a lot of potential sparkle. Still I can see where a very dark grout used with a light tile (raenjapan) could cause a bad result. I think both ck and sixty have beautiful backsplashes. Maybe the key is minimal grout width and low contrast.

I'm not a huge fan of glass or contemporary backsplashes, but I think ck's is esp. lovely.

cat_mom - this is also very good to know. I'm going to investigate that TEC XT grout and thank you for the suggestion. I'm worried about the same exact issue with the vent behind our stove - it points directly at the backsplash.

I originally considered doing a stainless steel sheet up to the bottom of the hood vent, but since our hood vent is actually 6" wider than our range, it would overlap on the edges of the countertop and I'm worried it would look weird being wider than the range.

Linelle I think you're right - minimal grout *should* let more light into the tile. We'll see what it looks like on the sample board.