How granite countertops are made

A kitchen slab is a sliver of rock that cooled slowly underground, cut and polished to just 19 or 32 mm thick.

stations: 6
things upstream: 1
raw source: 1
step from the ground: 1

The short version

A granite countertop starts as a big block cut from a quarry with diamond wire saws. The block is sawn into slabs 19 or 32 mm thick, and the slabs are polished. A fabricator then cuts each slab to the kitchen layout, shapes the edges and sink cutouts with routers and CNC machines, and seals the stone.

Cut a block from the hill

Dimension stone quarries separate blocks with diamond wire saws, diamond belt saws or light, selective blasting. Heavy blasting would shatter the stone.

Goes in
Granite
Saw it into slabs

Gang saws slice the block into slabs. Standard thicknesses in the United States are 19 and 32 mm, and thin slabs are sometimes laminated at the edge to look thicker.

19 or 32 mm thick
Polish the face

Abrasives give the slab a polished finish with high luster and a near-mirror reflection. Some countertops are left honed, a satin finish with no reflection.
Cut to the kitchen plan

A fabricator shapes the slab to the kitchen layout using cutting and finishing equipment. Holes for sinks and cooktops are cut at this stage.
Shape the edges

Edges are cut with hand-held routers, grinders or CNC equipment. Stone with a strong pattern may be laid out in the shop so the customer can inspect it first.
Seal the stone

Natural stone needs sealing so it does not hold bacteria or stain. Newer oleophobic impregnators have reduced how often it needs to be resealed.

End of the lineGranite countertop

Worth repeating

Granite is a coarse-grained igneous rock of quartz, feldspar and mica that cooled slowly from magma underground.
Some fabrication is done at the quarry, with blocks sawn to thickness and polished there, which saves shipping waste.