If you own a restaurant and have chosen to use porcelain for your crockery, or if you chose porcelain dishes to serve food on to your family, you probably did so largely because it is so tough and hard-wearing while still being elegant enough for presentation of fine cuisine. Having been fired at such a high temperature, it is dishwasher-safe, microwave-safe, heatproof, non-porous, quite non-stick, and totally suitable for food presentation. That being said, it certainly does not mean that porcelain is unbreakable, and reasonable care should be taken when handling all ceramic dinnerware.
However, not everything that is labelled "porcelain" is necessarily the same thing. Real porcelain is sometimes called "hard paste porcelain" because there is also "soft paste porcelain" which is sometimes made in Europe in imitation of the genuine Chinese porcelain. The soft paste product has a softer body (the shaped clay after the initial firing), and is slightly porous because the glaze has been fired at a lower temperature and so is a separate layer to the body. Hard paste porcelain has a glassy appearance, and is tough and non-porous. Fired at a higher temperature, the glaze is thoroughly fused to the body and the pieces can be thin-walled and almost transparent, at the same time as being strong.
Importantly, not all porcelain is used for eating and drinking, and the most precious collectible pieces can be extremely fragile simply by virtue of their intricate workmanship, and others are irreplaceable by virtue of being truly ancient and therefore in need of extra care.
Here are some things to consider when purchasing, handling, transporting, displaying, cleaning and repairing your precious porcelain objects.
When you are planning to purchase porcelain collectibles, you need to look very carefully to find any potential problem areas. Ideally, pieces should be handled as little as possible, but naturally if you are making a purchase you want to be hands-on. Make sure that you are not wearing jewelry such as rings, bracelets or watches, or anything that could scratch or damage the piece, and be aware that your hands could leave a residue on the surface of any unglazed pieces. Always support the object carefully with both hands, and don't pick it up unsupported by spindly or weak parts such as handles or stalks.
As you carefully handle each piece, you need to pay attention to any small cracks, crazing or pitting in the glaze, and check them out, watching especially for structural damage. A light fingernail tap should produce a ringing tone, a dull sound may indicate a flaw. Carefully holding the item up to the light may also expose any renovated parts or flaws. Look carefully at the surface for any sections that may be unstable and flaking or lifting. If the piece has previously been exposed to water you may see corrosion of metal parts, or stains in the glaze, or cracking.
Great care will need to be taken when you come to transport your newly acquired collectibles. If you are already aware of any possible weak points in the construction you will better be able to construct safe packaging. They need to be safe from jarring, and even vibration over an extended period can be damaging. Some items also need to be protected from any possible moisture.
There was a time when people would display their beautiful pieces of porcelain on their mantelpiece, but if you have purchased a priceless item, you will doubtless want to think about a slightly safer position. You may have a suitable display cabinet, especially for a number of pieces together, as long as they are not so crowded that they could jangle against each other. Hanging pieces by their handles may seem attractive, but is ill-advised as these are often a weak point. Vibration should be avoided, such as a springy floor, or vibration from a nearby road, as this can cause pieces to jiggle around and move. Sitting them on something soft such as chamois leather will keep your pieces safer. If the display is in a heavy traffic area, with people walking past possibly bumping the case, items may be damaged. You may want to invest in some specially designed plastic mounts to keep your pieces visible, dust-free, and safe.
Although washing your porcelain dinnerware in the dishwasher is fine, extreme caution is needed if you decide to clean your collectibles. First be sure that you are looking at a mark or something that really needs to be cleaned off, and whether it is possible to do so without causing damage. Before using any chemical or cleaner, be sure that you have identified the exact type of material you are looking at. Any already damaged parts will need extra care as liquids seeping into cracks in the surface will do more damage.
A decision to personally repair a broken porcelain piece will depend on its value. Special adhesives can be purchased that are suitable for damaged tableware. Ceramics curators have access to specialist adhesives that are not available to the public. If you have a valuable piece that needs fixing, you would do best to go to the experts rather than cause irreversible damage with unsuitable materials.