Thanks. These all look like custom made things that these companies would install? I was hoping for something we could buy online that our general contractor that’s redoing our bathroom could install. Has anyone tried anything like this:

https://www.superbrightleds.com/moreinfo/flexible-led-sheet-lights/lls-crgb-a12a-60a01-24v/6526/14590/

Or do strip lights like this work?

https://www.amazon.com/dp/B08DQYCMZ6/ref=cm_sw_r_cp_api_i_GTXJDC2ADXZYNPQJBC0W?_encoding=UTF8&psc=1

Will the flexible-led-sheet-lights work? Maybe, but if you look at the photos, you'll see the LEDs are pretty far apart. The green "C" looks evenly lit because the LED sheet is many inches from the green diffuser. If that sheet were pressed up against the marble, I think you'd see the LEDs as dots and the marble wouldn't be evenly lit.

Maybe you could put strips lights inside corner channels around and beneath the edges of the marble slab, all facing inwards, to illuminate the marble. Or use edge-lit channels all around the marble slab.

The best backlighting is accomplished in the design phase; retrofitting will be hit and miss at best.

"I was hoping for something we could buy online that our general contractor that’s redoing our bathroom could install."

1. What are the dimensions (length, width, thickness) of the counter?
2. Are you sure that the counter material is light-transparent?
3. What is the purpose of the counter (e.g., over a vanity, bench, wall)?
4. How will the counter be installed? How will it be supported? What will be underneath it and surround it?

It’s 65” long, standard bathroom counter depth. Not sure of thickness- it’s marble and yes has some crystal areas. Bathroom counter, double sink. The stone place is installing it over top of cabinets. We’re looking at maybe led sheet lights or led strip lights.

If it's a bathroom won't the room be brightly lit by ceiling lights or lights above or adjacent to the mirrors? Will people even notice that the countertop is lit from below? The photo you posted above was a countertop in a dark room so the countertop is visible and that countertop isn't chopped up with sinks, faucets, and covered with stuff people keep on a bathroom counter. I don't see any reason for this in a bathroom.

It would be for night time when it’s darker yes

I'd attach a strip light to the bottom of the mirror or medicine cabinet and have it shine down onto the countertop. I think that'll look better than illuminating the countertop from below or from the edge and having big, round dark circles where the sinks are. And it'll be far easier to install.

I think they were looking for a more artistic effect than a functional one.