How to approve marble samples and lots

Approving a marble sample means recording a reference for the chosen colour, texture and finish. Approving a lot means assessing how the actual material to be used in the order relates to that expectation. The two are not the same process. Do not assume that a small sample represents every slab exactly; the accepted range of appearance should be defined separately.

Do not leave a sample unidentified

Attach the material name, code, finish and dispatch date to the sample. If there is more than one sample with the same name, use different codes. Confirm that the samples held by the design team and by the fabricator correspond to each other. An approval described on the phone as “the white sample” may not explain, at the production stage, which stone was chosen.

Put the accepted appearance into words

Are warm veins acceptable? How dense can the dark veining be? Do calm areas or busy areas take priority? Answer these questions with photographs and samples. Rather than trying to eliminate natural variation, define the range you want in a way others can understand. Make it clear in the file that visual acceptance does not replace the assessment of technical suitability.

See the actual lot at a large scale

Review the photographs of the slabs to be shipped, their codes and, if needed, the layout plan together. The edges of each slab should be visible in the photographs. A close-up of the most beautiful area alone may not represent a large surface. If more than one slab will be used, assess how they look together. Allow for the fact that different lots can look different under the same product name.

Manage approval with a revision system

Give the approved document a date and a revision. When another slab is proposed as a substitute, state that the previous approval does not automatically apply. See which pieces and neighbouring surfaces the change affects. The last approved file should be the single reference the cutting and shipping team can access. Use an organised handover file rather than photographs scattered across emails.

Which reference will be used at delivery?

When the material arrives, check the bundle codes against the approved list. If there is a claim of visual difference, it helps to assess it in the same light and conditions. Stone that is wet or dusty should not be compared directly with a clean, dry sample. Agree, in line with the scope of the contract, who will carry out acceptance, when, and with which documents.

During selection with Mabella, collect the sample and lot documents under the same project code. This helps the design preference keep the same meaning all the way to order and shipment, and moves the discussion away from personal memory to a reference everyone can see.