Guides · Materials
How do you pick a marble slab?
In short. Slabs cut from one block are not the same slab: they come out in sequence and the drawing migrates from one to the next, which is what makes bookmatching possible. So the choice does not end at “I want this marble”. It ends when it is written down which slab, where your piece is cut from it, and where the joints will fall. Whatever is left unwritten still gets decided — just not by you.
“They are all the same, they come from one block”: is that true?
It is the sentence you hear in the yard, and it is true and false at once. True about the material: one block means one quarry, one bench, one quality. False about the drawing — which is the reason anyone chooses a marble at all.
A block is sawn into parallel slabs, all in the same pass, and they come out numbered in the order in which they sat inside the stone. From one slab to the next the drawing moves: a vein crossing a corner on the first slab may sit in the middle of the tenth and be gone by the twentieth. Not a defect: the structure of the block revealing itself layer by layer.
And the saw removes material too: diamond wire works with wires of around three tenths of a millimetre, traditional blades take a few millimetres at every pass. Between two “twin” slabs there is always a thickness of stone gone to dust. The mirror is extremely close. It is never exact.
Why is a sample not enough to decide on?
Because a sample tells you what the stone is, not what your piece will look like.
The UK stone federation’s code of practice for stone counter tops, the clearest trade text on this point, puts it without hedging: samples of only 100 mm by 100 mm should not be used for the final selection of horizontal surfaces, and every sample should carry the statement that it is indicative only. And where a large quantity of stone is used, the slab selected should show the full range of variation — not its most photogenic corner.
A sample rules things out; it does not tell you whether one vein or two will cross your table.
In what conditions should a slab be looked at?
In a yard slabs stand upright, often with light raking across them; the finished piece will almost always lie flat, under different light. The same code warns about this: the appearance of slabs seen stacked vertically and in bright natural sunlight will change once the stone is installed horizontally.
Three habits change the decision. Look at it wet, if the surface is still sawn or honed, because water comes close to the appearance polishing will give. Photograph it whole and square on, never at an angle, together with its number. And look at it against the light, if it is onyx or a stone to be backlit: backlighting reveals translucency, repaired fractures and differences in thickness that reflected light hides. It is why every slab is examined against the light in our workshop before it is cut.
How do you make sure they cut that slab and not another?
This is the real question, and almost nobody addresses it — while on renovation forums it recurs with striking regularity: someone picks a slab, tags it, and weeks later finds a different stone installed, because the tag had stayed on the wrong slab. A tag, after all, is not a document.
What counts is something else, and the code of practice is explicit: the manufacturer should ensure the selected slab is signed as approved by the designer or customer in indelible ink.
Sign the slab, not merely choose it. The rest is built around that: write down the slab and block numbers and have both put on the order — an order that says “Calacatta marble” identifies nothing, one that names slab and block identifies a single object in the world; keep the square-on photograph with the number; and ask for the slabs intended for one job to be consecutive, as the code prescribes for directional markings, which should all run the same way.
Where will the joints fall, and who decides?
Someone decides in every case: the only choice is whether it is you or the cut. The trade principle is that, where drawings do not show the position of the joints, it should be agreed between supplier and customer before fabrication begins. Silence is not neutral: silence is a delegation.
On width there are precise references: where two worktops abut, the joint should be within one and a half millimetres, with half a millimetre of tolerance; against a vertical lining, up to three. But a good joint is not only a narrow one. It is placed where the drawing forgives it: off the line of sight, never at a hole or a cut-out, where the stone is already weakest.
Bookmatch, vein match, random laying: which do you need?
Bookmatch opens two consecutive slabs like the pages of a book and mirrors the veins across a central axis: it requires them polished on opposite faces. Vein match carries the vein across the joint as though the cut were not there, and requires slabs polished on the same face. Random laying gives up symmetry for chromatic balance across the whole.
There is one practical consequence: the choice between the three carries with it the face on which the slabs must be polished. If they are already finished, some routes are closed. “We will decide later” is a decision even when it does not feel like one, and usually the one that rules out bookmatching.
What belongs on the order
The name of the stone, written out in full. The European standard on the denomination of natural stone asks for four elements — the traditional commercial name, the petrographic family established by laboratory examination, the typical colour, and the place of origin down to the municipality and country — and advises against geographical names unrelated to the actual origin, and against company names used as denominations.
Then: the slab and block numbers; thickness and finish; the layout of the pieces on the slab, approved on a photograph before cutting; the position of the joints. And the survey: horizontal surfaces should be made only from full templates taken on site or accurately dimensioned drawings — paper and cardboard will not do, because they do not hold their dimensions.
How we work
We work natural stone — marble, onyx and hard stones — and we select the slabs ourselves, one at a time, in our own workshop. Every slab is examined against the light before it is cut: the check that brings out what reflected light hides.
We do not use resin to stiffen slabs: large surfaces do need support, and the mesh applied to the back is already a good one, but reinforcement belongs in the structure carrying the top, not in an additive in the material.
Stoneform and Brianform are two divisions of one company, with production in house: between whoever draws the piece and whoever cuts it there is no commercial step. It is why the layout on the slab is something you discuss rather than something you receive.
Tables · Works · Commissioned work · Write to us
Frequently asked questions
Can I choose the slab myself, or does the supplier decide?
You can, and on a bespoke piece it is normal that you do. The part that matters comes after the choice: having the slab and block numbers written on the order, and approving the layout on a photograph before the cut.
How much more material is needed than the size of the top?
More than people expect: the piece has to sit where the drawing is right, and edges and aprons need offcuts of their own. On thicknesses and overhangs, how thick should a marble table top be; on price, how much does a custom marble table cost.
If the marble stains later, does the choice of slab have anything to do with it?
Very little: staining and etching depend on the finish and on use, not on the drawing, and we have written about that in marble stains and etching. The slab decides how the piece is made, not how it ages.
Ask for a quotation The tables collection
The points on samples, viewing slabs, approval signatures, the position and width of joints and templating are drawn from the UK stone federation’s code of practice for natural stone counter tops. The four elements of a stone’s denomination — commercial name, petrographic family, typical colour and place of origin — are those prescribed by the European standard EN 12440. The cutting widths quoted are figures published by manufacturers of diamond-wire and blade saws. None of this replaces the written terms of an individual order.