My marble threshold shelf is finished! I'm so happy with how it turned out - thanks to the willingness of the tile guy to work with me! I thought I'd share the pics and how to as this was simple and inexpensive.
I bought a 6" x 36" marble threshold for about $12 and a package of four 3" angle brackets for about $3.
The tile guy cut the shelf to my specifications, 4" x 30". I showed him roughly where I wanted it to go. It is about 12" above the countertop.
As he was installing the tile and knew where the grout lines would fall, he screwed the brackets into the wall so that they would fall on a joint and applied the mastic over it. (He might have recessed them by carving away a little of the drywall - I was not there when he did it but we had talked about it.) Then he applied the tile over that and grouted the whole thing.
The threshold came with a slightly beveled edge so that when it is used on the floor, the grout fills the space between it and the next tile. It was whiter and rougher than the polished top, as were the edges he cut. So I applied three coats of clear nail polish on the edges and that made it nice and shiny and you can now see the veining on the edge as well as on the top.
I did not attach the shelf to the brackets. I figured it would be easier to clean the backsplash if I could take the shelf off.
They do sell 4" thresholds and the tile guy asked me why I didn't just buy one of those. I told him it was because I didn't like the veining on any of those. He just sort of laughed at me but I knew you all would understand! I sorted through every threshold on the shelf at the store to pick out the prettiest one.
I hope this is helpful to someone planning something similar!
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