We normal use a quartz man-made stone with a some sparkle to it but mostly just white. Just about every brand and every fabricator can produce this look and will have a something with that sparkly white look. The edge is simply fabricated to a nice thickness - typically the smallest I will do is 2 1/4" up to about 4" like this one.
I designed it and had it built by a local metalworker, I got the glass from a commercial supply house, the cost of custom fixtures is normally fairly comparable to high end stock ones, we did four of this one in two different configurations so there was some saving in repetition though they each contained about 70 individual pieces of metal.
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