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Answer

How do you avoid the natural cracks in Giallo Siena marble?

What happens before it is a surface

A slab on the saw table, being taken to the sizes a cut list asks for
A slab on the saw table, being taken to the sizes a cut list asks for

You do not avoid them in the block — they are part of it — you avoid them in the piece. The cracks are visible in the block before sawing, and the buyer has to judge whether a crack can be avoided when cutting to the required size. Repairs are made during processing, and what is not repaired is an imperfect piece.

The figures

StageWhat happensSource
In the blockNaturally formed cracks are visible before cuttingPublished material note
During processingUnrepaired cracks leave the finished piece imperfectPublished material note
The decisionWhether a crack can be avoided when cutting to the required sizePublished material note
Before it is sawnVacuum resin treatment closes the small holes and cracksPublished block and slab characteristics

Why this stone behaves this way

Giallo Siena marble is a breccia, and a breccia carries the fractures that formed it. The resin treatment closes the small ones so the slab can be cut and polished; the structural ones are a matter of where the cut falls.

What these figures are, and what they are not This is about the material as it is. It is not a statement that any particular slab is free of them, and a crack that has been repaired is still part of the piece.

Where these figures come from

  • S1 granitalsiena.com — Giallo Siena marble technical sheet (EN standard test values; Politecnico di Torino marble laboratory)
  • S13 stoneembassy.com — Giallo Siena specifications and slab grading

Where to go next

On the same subject

More questions about Giallo Siena marble

How is Giallo Siena marble bookmatched?

Consecutive slabs from one block are opened and laid face to face, so the movement of the stone mirrors across the joint and reads as one surface rather than as a series of panels.

What does resin backing do for Giallo Siena marble?

It closes the small holes and cracks so the slab can be cut thin and polished.

Fabrication questions

More on this subject

This answer sits on the What happens before it is a surface page, with the rest of the questions about it.

Fabrication

Ask for a price

A thickness, a format, a finish, a quantity and a destination will get you a quotation for Giallo Siena marble.

How do you avoid the natural cracks in Giallo Siena marble?