Specify the lithology, lot and visual range—not just “marble.”

Compare background tone, translucency, grain/crystal structure, veining, spotting, repairs and lot continuity.

Approve a current multi-slab or tile range. Heritage or locality wording does not define grade, whiteness or quarry.

Separate the commercial marble category from possible serpentine/serpentinite lithology and compare movement, fissures, mesh and treatment.

Require source-linked petrography before selecting the governing material specification or making geological claims.

Compare directional veins, branch-like movement, brecciation, fissures, reinforcement, slab sequence and cutting direction.

Use full-slab/bundle approval and disclose mesh, resin, fill and repairs; small samples cannot represent movement.

Compare base colour, vein contrast, shade range, polish response and treatment on the current lot.

Approve colour under controlled light and test the exact finish; colour names are not performance or origin claims.

Resolve whether the offered material is calcitic banded stone, true onyx, another lithology or a look-alike before specification.

Require petrography, translucency/lighting mock-up where relevant, reinforcement disclosure and fragile-fabrication planning.

Separate imported origin, protected/geographic naming, Indian look-alike supply and unsupported catalogue wording.

Quarantine enhanced discovery claims until supplier, country, quarry/program, chain of custody and naming scope are approved.