Identify the lot
Record the trade name, source, block numbers and slab IDs. State where the same-block requirement applies, such as a continuous floor or a bookmatched wall. Agree an acceptable range of variation with representative samples.
Require numbering in cutting sequence where the design depends on it. Include a dry lay or photographed sample batch as an approval stage before full dispatch.
Define acceptance
Write the finish, nominal thickness and permitted tolerance. State the measurement basis, allowed repairs and treatment disclosures. Numerical tolerances should be agreed for the specific job with your fabricator or specifier.
Allocate responsibility for pre-shipment inspection, packing, freight, insurance and notification of defects. Reference the approved documents so photographs and measurement sheets form part of the agreement.
Think about the repair later
Consider holding a project-specific reserve from the same lot for cuts and future repairs. The quantity depends on the layout, stone variation and repair risk. Make ownership, storage location and release terms explicit.