First, let's talk about the main points: In summary, the choice of ceramics should be divided into three steps: thorough examination, lighting and scratching with a knife.
Touch the bottom
When buying crockery at home, don't look for a colorful plate that looks good, but buy it right away. Now the market is full of good looking products but bad material. General ceramic dinnerware is baked on the oven table. Therefore, the handle part of the foot (ceramic bottom) is generally not glazed. Just because there is no enamel coating, the ceramic body material can be seen directly and clearly. Then take a plate and turn it over to see the color of the bottom.A good porcelain handle should be white, delicate and smooth to the touch.
Poor China has its problems. The image below is a dish I found in a nearby supermarket. Look closely, there are obvious black spots where circles and triangles are marked. This means that the porcelain has obvious flaws. It is better not to buy such a dish. The area marked with the rectangle shows that the enamel layer is not completely covered. This is also one of the flaws of ceramics. Also try to avoid it when buying.
Second, take out your phone, turn on the flashlight and look through the plate. Note that at this point, don't believe the employee is telling you that you see him transparently or otherwise. It does not matter if it is transparent or not, but if the transparent part is uniform and free of impurities. If you can see through the light that there are distinct black dots, then don't buy it. The translucent part of a good ceramic is very uniform.
The rest of the pottery pictured below is fine. But there is a noticeable black spot inside after the light transmission. This shows that the ceramic body itself has impurities.
In fact, there is no absolute correlation between the transparency of a piece of ceramic and the quality of the material. Of course, if the plate is made thinner from the same material, it will become more transparent, but if the plate is made thinner, the strength will naturally decrease and the thermal insulation performance will be relatively weakened and it will get a little warm when used. The same thin and thick plate material has different light transmission performance. Bone china is more transparent than hard-paste porcelain because the internal structure of bone china is relatively loose and hard-paste porcelain is denser. It is not good or bad based on that alone.
Cut with a knife
Using a knife can be overkill, but let's talk about the principle inside. Scratching with a knife is actually about two things. One represents the hardness of the glaze surface.Under normal circumstances, the hardness of the ceramic glaze surface should reach a hardness of 5 Moh, and ordinary hard objects will not leave marks on the ceramic surface. If you scratch the surface of the ceramic with a knife and a black spot appears, in a few days your plate will become a cat with a face. The second purpose of scratching with a knife is to scratch the surface pattern. Decorative patterns on the normal ceramic surface are fired at a high temperature. It will not fall off during normal use.If you scratch it with a hard object and it falls, it means the decoration process is not sufficiently qualified. It peels off with daily use, not only is it unsightly, but you can imagine where all that peeling paint goes.