Test reports generally quantify the physical & chemical properties. All factories at Morbi use more or less the same machinery (press, kiln, polishing line) and also similar raw materials. So both these (physical & chemical) properties will be within the acceptable norms. But most quality issues are related to visible defects. Some of them are listed below... - Shade variation - Edge polishing is not proper - glaze bubble - black spots on white tiles (contamination) - pinholes For test reports few samples are submitted (generally 4 pieces) to a ceramic lab. One such test report for 60x60 GVT tiles is uploaded here just for your reference. The physical & chemical properties accessed from such reports are valid for all products of that batch. But surface quality (listed above) can vary within a batch. It needs to be controlled on-the-line at the sorting area. So apart from reports, you need to check the sorting area of the factory and ask questions on how they mark the tiles for 1st, 2nd, or 3rd choice.