Where a black pebble comes from
The dark stones are generally basalt and other volcanic and dark metamorphic rocks, rounded by water in the same way a pale pebble is. A black beach or riverbed is a beach downstream of dark rock.
Some black pebble in the wider market is color enhanced rather than naturally dark, which is a normal trade practice and a thing worth knowing. Where it applies to a specific product it is stated on that product's page.
Shadow does all the work
On a multicolor sheet the eye sorts the stones by color and the shape comes second. Remove the color and there is nothing left to sort by, so the shape and the shadow between the stones carry the whole surface.
That is why a black pebble floor looks more sculptural than a pale one. Every dome catches a highlight at its top and throws a shadow at its base, and the surface reads as relief rather than as pattern.
The joint matters more here than anywhere
Pebbles touch at points, so the space between them is wide and deep, and on a black sheet the joint is the only other color present.
A dark joint disappears and the floor becomes one continuous dark relief. A pale joint outlines every stone and turns the sheet into a graphic of circles. There is no middle result: the choice produces two completely different floors from the same sheet.
Natural and polished
Most of this small range is natural, with one polished blend, and the difference on a black stone is larger than it would be on a pale one.
A natural black pebble is matte and absorbs light, so the shadows dominate. A polished one returns a highlight from every dome, and a wet or lit surface of them glitters. Natural is the usual shower choice and polished the one used where a wall is meant to be seen.
The blends inside a black sheet
The series names here run to charcoal, obsidian, a mixed black and a flat version, and those are describing how tight the sort is rather than a different stone.
A tightly sorted black sheet is uniformly dark and reads as one mass. A mixed one leaves grays and near-blacks among the black, and at close range the surface separates into individual stones again. The first is the more dramatic and the second is the more forgiving.
Sheets and coverage
Almost every sheet here is 12x12, with a 9 7/8x11 7/8 alongside it, all at 3/8 inch thick.
A 12x12 pebble sheet covers a square foot, which is a tidier relationship than most mosaics manage. The edges are where it departs from that, since a pebble sheet is trimmed around the stones rather than cut through them.
Where a black pebble goes
A shower floor, a steam room, a spa surround, a band inside a pale tiled floor and a wall panel where the relief is meant to be seen rather than walked on.
Pebble mosaic carries the other blends, and black tile and mosaic the rest of the color.
