How to judge the quality standard of natural stone

Appearance quality also includes appearance defects, such as lack of edges, corners, cracks, stains, color lines, pits, marble sheets, and appearance defects such as warpage, depressions, and stains. “In the standard of natural granite and marble building boards, the appearance quality index stipulates that the color tone pattern of the same batch of plates should be basically reconciled, and the appearance defects are not allowed in the superior products.” Yang Xinli introduced that the defect detection method is: the plate to be inspected Flat on the ground, defects visible at 1.5 m from the plate are considered defective; not obvious at 1.5 m from the plate, but defects visible at 1 m are considered as no obvious defects; invisible from 1 m from the plate Defects are considered to be defect free.

3 ratios measure processing quality

“The processing quality of stone directly affects the decorative effect of stone veneer, and it is also the main basis for the classification of stone grades.” Yang Xinli introduced that the technical indicators are specification dimensional deviation (length deviation, width deviation, thickness deviation), flatness tolerance, angle tolerance. According to the deviation and limit tolerance of these technical indicators, the plates are divided into superior products, first-class products and qualified products. Yang Xinli suggested that consumers should stipulate the level to be achieved in the purchase contract and avoid using the generalized products such as “reaching national standards”. “In each batch of products, if it is a superior product, more than 5% of the first-class products are not allowed. If it is a first-class product, more than 10% of the qualified products are not allowed. If it is a qualified product, it is not allowed to have more than 10 % of non-conforming products exist."

3 gloss units

According to Yang Xinli, in the stone standard, the gloss is called the specular gloss. The current standard for natural granite slabs stipulates that the front side of the mirrored sheet should have a specular gloss that clearly reflects the scene. The mirror gloss value of the mirror plate should be no less than 75 gloss units. “When most granite plates have a gloss value of 80 to 90 gloss units, they have a good specular gloss.” Yang Xinli suggested that consumers should indicate the gloss in the purchase contract according to their different requirements. Value, or according to the gloss value of the protocol board as a standard. “The gloss values ​​are graded in the current natural marble sheet standard. The minimum gloss value of the superior products is divided into three categories according to the chemical main components, which are 90, 80, and 60 gloss units, respectively.”