Because stone is a natural material, it has many unavoidable defects, and defective stone products are unacceptable to customers, so many factories will cause huge waste and loss. Some stone factories will treat these sub-products as first-class products (A-class products) and sell them to customers. Of course, the price is cheaper. Therefore, in the factory inspection, we must open our eyes to confirm each piece of qualified stone products. Otherwise, it is the claim of the customer, and the loss of the customer.
Usually, the main methods of treating secondary stone into first-class stone in stone factories are as follows:

1. Use wax to repair holes in slabs (especially granite)
It’s not safe to do this. The correct way to do this is not to make up wax, but epoxy resin, which is the same or similar color as the surface of stone. Wax is used to repair holes. Once wax falls down halfway or wax melts due to factors such as sun exposure and high temperature environment or fumigation in containers, the holes will still appear at last. The board surface is very good when checking goods, but there are holes on the board side of customers.
So how do you distinguish the stone repaired with wax?
At this time, as long as we pay attention to some unnatural crystals (crystalline particles) on the surface of the stone plate, those are often impersonated by paraffin.
2. Because the polishing degree is not up to the standard, oil, wax and film are used to increase the glossiness of stone.
Because of their own processing technology or cost considerations, some stone processing plants did not grind the stone to meet the contract standards or requirements of glossiness, so the use of polishing oil, or wax, and coating film to increase the glossiness of the stone surface, so as to make it meet the contract requirements of glossiness (generally more than 90 degrees). The effect is also very bad, such as oil and wax, may not be installed before the time (or installation process) will reveal the stuffing, while the coating is better, but once the film is worn out, it will also reveal stuffing, for some orders with due date is quite dangerous, may be empty of money and goods.
So how do we distinguish the polished stone products?
Generally, the back and side of the oil-coated stone products will have oil stains, even oil spots; the wax-coated stone sloping Kanban surface is also somewhat different, you can use matches or fire to bake the board surface, if there is wax, it will be copied to reveal the original face of the stone; as for the wax-coated stone, although the gloss is very high, No. The strength of the general film is not good, easy to be worn and scratches can be seen by light.
3. Treatment of defects such as black gallbladder and stains
For the black and gall stains of stone, they are usually treated with strong oxidant, which is the same in most factories. But there are differences between good quality factories and poor quality factories. Good quality factories will be treated after rough grinding, then rinse clean without leaving any oxidant residues, and then fine grinding. And the factories with poor quality control are polishing first. When checking goods, they pick out the defective stones such as black-and-gallbladder color plate before processing. They are smeared with strong oxidizer on the spot and washed on the spot. The stones that can be treated are basically collected by quality inspection. In fact, this is also problematic. Firstly, the treated sheet is corroded by strong acid or alkali, the surface of the plate is damaged and the gloss is reduced. Secondly, on-site washing of strong oxidizers and rushing to pack boxes will result in unclean washing of strong acids or alkalis on stone slabs, which will cause these residual strong oxidizers to continue to oxidize and cause problems such as chromatic aberration and whitening to destroy the surface of the slabs. Moreover, due to being washed by water, these strong oxidizers will flow to other places and cause two. Secondary pollution, its pollution scope is often much larger than the smear area.
How to deal with the defective stone with black gallbladder and stain?
For this problem, it is better for us to inspect the goods when the time is more abundant. If there are stains or gallbladders that need to be dealt with, we must clean them and then send them to polish them.

4. Dyeing chromatic aberration stone, or using other stone to replace dyeing.
For dyed stones, first of all, they need to be recognized by customers. Never use dyed stones as first-class products. For and even if it is dyed stone, it should be evenly colored, with good color fastness and can not fade.
So how to distinguish dyed stone?
The color of the dyed stone surface will be more gorgeous and unnatural. If we break the sheet, we will find the dyeing penetration layer at the fracture of the sheet. There are also natural stones that can be dyed in general. Their stone quality is not good. They are some stones with large porosity and high water absorption (which will affect the physical and technical properties of stones and are prone to accidents). Generally, they can be distinguished by knocking method. The sound of stones with dense texture is relatively clear and crisp when knocked down, while the sound of stones with loose texture is relatively clear. The sound is rather dull. There is also the same kind of natural stone, after dyeing, its gloss is lower than that of non-dyed stone, it seems a little dim.