Why granite does not etch
Marble, limestone and travertine are carbonates, and an acid dissolves a trace of their surface. Granite is a silicate rock, and neither the quartz nor the feldspar in it dissolves in anything a kitchen holds. Lemon juice, vinegar and limescale remover leave a dull mark on a carbonate stone and leave granite as it was.
Sealing answers a different question, and the two get confused constantly. Some granites take up a little liquid and are sold with a sealing regime, which slows how fast a liquid enters the stone. Etching is chemistry and absorption is porosity, and a sealer speaks to the second one.
What the trade means by black granite
In the stone trade granite is a commercial category. Most dark stone sold as black granite is a gabbro or a dolerite, built from feldspar and pyroxene with little or no quartz. Absolute Black and Black Galaxy sit in that group, and Blue Pearl is a larvikite. All of them are silicates, so the acid behavior described above holds for them too.
Polished, honed and flamed
Polished is the largest finish group in this collection, honed is second, and a small flamed group follows. A polish on granite is the stone's own surface refined until it reflects, and the crystals doing the reflecting are hard, so the shine holds up far longer than it does on marble. Grit carried in on shoes still wears a polished floor down slowly in the busiest paths.
Honed is the same stone ground flat and stopped before the shine. A honed black reads deeper and quieter, closer to charcoal slate than to glass, and it hides the footprints and water spots that a polished black shows under a low window.
Flaming passes the face under an intense flame, the minerals expand at different rates and the surface lets go in grains. Every flamed tile in this collection is Absolute Black, and because the rough face scatters light, a flamed black comes out a soft dark gray. Marble and limestone are rarely flamed, since a carbonate heated that far breaks down at the surface, and those stones are usually tumbled or sandblasted for texture.
Absolute Black is offered polished, honed and flamed in the same four sizes, 12x12, 12x24, 18x18 and 24x24. One stone can therefore go down polished in a living room and honed or flamed in the kitchen next to it without changing color.
Granite colors by name
Black is well over half of the collection. The other colors come one name at a time: Ubatuba is the green, Baltic Brown and Tan Brown the browns, Blue Pearl the blue, New Venetian Gold the golden yellow. Those five come as polished 12x12 squares.
Granite usually carries its figure as a crystalline speckle where marble carries veins. Baltic Brown is the exception worth knowing: it is a rapakivi granite, with large rounded feldspar crystals ringed in a lighter rim, so its pattern reads as dots on a dark ground. A black granite reads as a solid surface with a fine grain in it.
Tile sizes and thickness
12x12 leads, then 18x18, with 12x24 and 24x24 level behind it. The interior tile runs at 3/8 and 1/2 inch, the larger squares at the thicker of the two. A small 1x2 polished black mosaic covers a backsplash.
Granite runs at roughly 2.6 to 2.8 grams per cubic centimeter, and the dark gabbros and dolerites run a little higher, against roughly 2.3 to 2.4 for porcelain. A granite tile therefore weighs more than a porcelain tile of the same size and thickness, which is a factor a wall installer weighs when choosing the setting material.
Granite in other formats
Outdoor granite is sold on its own pages: flamed Gray Mist and White Mist pavers under stone pavers, the same stones with a pool edge under pool copings, and Belgian block and cobblestone under granite pavers and cobblestone. Countertop pieces are under granite slab.
Granite against quartzite and marble
Quartzite began as sandstone and was recrystallized, so it carries movement and veining closer to a marble's, while granite usually shows a speckle. Quartzite is also less consistent as a trade name: a fully recrystallized one is inert, while some stone sold under the name still carries carbonate, which reacts to acid. The quartzite slab range covers it.
A kitchen floor is the case granite chemistry suits best, followed by a hallway, an entry, a bathroom and a commercial floor, all of which ask for hardness and none of which asks for figure. Marble tile is the stone most people weigh it against, and the choice usually comes down to whether the room wants veining or an even ground.
