Quality Control Standard

Quality Control Standard of RefineStone Industrial Co.,LIMITED

As an international world-class stone supplier, RefineStone Industrial Co.,LIMITED adheres to the principle of “First Quality, First Credit”. We always pay great attention to the quality of every shipment of stone products. Before shipment, we have our own Quality Inspectors stay at the workshop to check almost every piece of the stone products, so that we can do quality to the customers’ most satisfaction. During or after inspection, we could take the pictures including stone products, packaging and container loading and send them to customers if required by customer. Meanwhile, we also welcome clients to check product quality by either personally visiting our production sites or employing any third independent party or inspection companies. Each order will be followed and monitored from the very beginning to the end by our experienced Quality Inspectors(QC) to ensure the quality is right and the delivery will be punctual.

As far as the stone products are concerned, the quality of stone products include the following 3 parts.

1)     Part A: Natural Stone Defects, something regarding the inner character of the stone itself.

2)     Part B: Stone Finish, Stone Workmanship

3)     Part C: packing method or packaging materials to be used, such as wooden crates, wooden bundles, polybags, one-ton bags, etc.

Part A:  Natural Stone Defects(Inner Character)

Granite or stone itself should be grade A quality, if the stone products include the following defects, we will have to pick them out.

1.       Color Line.


2.       Two different Color Shade in a piece of stone.


3.       Color Difference


4.       Veins


5.       hairline vein


6.       holes (tiny, small or big)


7.       Spots (could be black, white, green, depending on different stone).


8.       Crack


9.       false crack.


And other possible defects depending on specific stone color.

For further details, you may check our Column of Stone Defects on our website.

Part B: Stone Finish, Stone Workmanship.

1.       Chips or broken edges, chips or broken edges are not allowed on the exposed/external surfaces of the products. Our company will NEVER accept the “repair” by cement or glue or others for those chips on the exposed/external surfaces of the products.

2.       Referring to tiles or cut-to-sizes, the 90-degree angle should be guaranteed on the corners. What is more, the two diagonals of the tiles or cut-to-sizes should be the same.

3.       Evenness of the stone tile or cut-to-size.       If length <= 400mm,flatness tolerance: +/-0.2mm
If 400mm < length < 1000, flatness tolerance: +/- 0.5mm
If length >= 1000mm, tolerance: +/- 0.8mm

4.       Bevelling or chamfering on the edges. If chamfering is done on the tiles/cut-to-sizes, please make sure all 4 edges are done evenly. Someplace bigger and someplace smaller chamfering is not allowed.

5.       Polishing Degree:
Polishing must be uniform throughout the whole slabs/tiles and in photometer as follows:
For black slabs / tiles : polishing +95 in photometer
For colored slabs/ tiles : polishing +85 in photometer.
Grinding wheel marks are not allowed on the polished or honed surfaces.

6.       Flaming, Bush hammered, fine picked, chisselled, hair lines surfaces.
Flaming must be uniform throughout the whole slabs/tiles, if somewhere not flamed adequately, we should flame it once more. Other surface finishes listed in this column must follow the similar quality standard.

7.       Scratches are not allowed, especially on the polished surfaces. Scratches might be not allowed either for the flamed, bush hammered, chisselled, fine picked surfaces, etc.

8.       About the size tolerance.   For thickness,:
                         +/-1.0mm in tolerance for slabs;
                          +/-0.5mm in tolerance for tiles

For Length And Width:
+/- 0.5mm in tolerance for tiles and slabs (not apply to the random edge slabs).

9.       Non-exposed sides, for example, unpolished Sides of the slabs/tiles should be at least flat cut.

10.    Stone products including tiles, slabs, cut-to-sizes, steps etc should be at least cleaned for all the exposed surfaces. As it is a “commodity”, we need to make sure they are clean before shipment.

11.    Free Allowance Regulation. For raw slabs with edges not cut(rough edges on all 4 sides), we normally provide some free allowance. It is a normal standard for Chinese Granite and Marble Slabs, we give 5cm in length and 3cm in width for free. For imported granite or marble, we do give free allowance, but the regulation is different for different stone, please check with us before ordering.

12.    Some more quality standard for the countertops.

1)       For the front full/half Bullnose, Ogee, Flat polished edge, etc, we need to make sure of the evenly polished, and the polishing degree of the front edges should be almost the same as the top surface of a countertop.

2)       No chips or broken edges for all polished surfaces

3)       Pay attention to the position of the sink cutout, faucet hole.

4)       For the 4cm laminated countertops, please make a nice seam, so that the seam won’t be seen easily.

13.    Some more quality standard for the culture slate/quartzite veneers (facades).

1)       For the exposed top surface of the slate veneers, no glue remains are allowed.

2)       There should be no holes even no small holes between each “small slate strips”, as slate veneers are made of many pieces of small slate strips.

3)       Evenness of the back of the slate veneers should be guaranteed.

4)       Glue the small slate strips as much as possible, so that there will be no holes between the strips. Make sure the slate veneers will NEVER come unglued.

5)       Please pay attention to the general thickness range. For example, if the size is 60x15x1.5-2.5cm, please make sure the thickness will NOT be beyond the range of 1.5 to 2.5cm

6)       All the small strips (for combination into a finished slate veneer) should be cut with a 90-degree angle on all 4 sides, and evenly cut on all 4 sides, so that the finished slate veneer will not be penetrated by the sunlight.(it means no gaps between each small strips are allowed for this kind of slate veneer)

7)       Pay attention to the overall look of the colors of the materials. Unlike granite, for slate veneers, we can NOT expect it like the granite uniform in colors. But we still need to make sure the overall look of the colors will be the same.

8)       Scratches are not allowed for the slate veneer on exposed surfaces.

Part C: packing method or packaging materials to be used.

1.       In general, the packing should be strong seaworthy wooden crates, pallets, bundles or one-ton bags(only for pebblestone)

2.       Wooden crates or bundles should NOT be exposed to the rain. As in many European countries, America, Canada, Australia, etc, they have the regulation of the wooden crates / bundles being without any worms, while the wet condition will come out of worms possibly.

3.       No worms, barks are allowed for the wooden crates or bundles.

4.       When loading the containers, normally we put only two layers, one crate on the top of the other crate. We usually do NOT suggest putting the 3rd crate on the top of the first 2 crates to make it 3 layers.

5.       For slabs, we use the wooden bundles. For other products like tiles, steps, cut-to-sizes etc, we use wooden crates. For thick kerbstone or other thick stone more than 5cm thickness, we can use the wooden pallets. But for wooden pallets/crates/bundles above 180cm in length, we strongly suggest that we will have to add the wooden slip strips onto the bottom of the crates/bundles/pallets for easier loading and unloading of the goods.

6.       For extremely long crates/bundles, please use more wooden feet to the crates/bundles, so that the stone will NOT be broken easily and the crates/bundles will be stronger.

7.       Shipping Marks are required on each wooden pallet/bundles, so that the customers can easily recognize their own goods

8.       When packing, polished surface should be against polished surfaces, so that the polished surfaces will not be scratched.

9.       After packing stone into the crates / bundles, please use strong plastic or metal packing belt to strengthen the wooden crates/bundles.

10.    Design and external sizes of the crates/bundles should be reasonable, so that we guarantee we can load as many crates/bundles as possible into a same container, and try to use the container space as much as possible, so that our customers will save ocean freight.

---Taking Measurement of Thickness by our Quality Inspectors:


---Quality Control Reference pictures.