Today, the purple clay industry is full of mixed quality products, making it hard to distinguish the genuine from the fake. Sometimes, you might doubt the authenticity of the purple clay Teapot you've bought. Both inside and out, purple clay Teapots will have some marks or traces; don't worry too much about these. Today, let's take a look at some commonly misunderstood features:

One: Threads of Lines on the Bottom of the Pot

Often, in the bottom of a Purple Clay Teapot, you can see a radial pattern radiating outwards like sunbeams from the center, known as the “sun line.”

▲ “Sun Line”

The technique of “wall scraping” has been passed down since the era of Dabin. The purpose of scraping the bottom is to remove any remaining clay marks and unevenness from the joining process. Some do it for decorative purposes, or to scrape away uneven shrinkage lines on the inner walls of the pot. However, scraping cannot be done too thoroughly or deeply, otherwise, excessive force could deform the body of the pot. Generally, just achieving the desired effect is enough.

▲ Wall Scraping

Two: White Powder Inside the Pot

Purple clay teapots are fired at temperatures exceeding a thousand degrees Celsius. During firing, the lid and the body of the pot are not fired separately but as one piece, because if they were fired separately, the lid would likely deform or become damaged, and it might not fit properly with the mouth of the pot.

To prevent the rim of the lid from sticking to the inner rim of the mouth due to “thermal expansion” during high-temperature firing, the maker will apply a layer of quartz sand along the edge of the lid before placing the teapot in the kiln. After the teapot is fired and cooled, this sand will fall into the pot.

▲ Before Firing

This quartz sand is completely harmless. In daily life, tap water and bottled water often pass through one or more layers of quartz sand during their purification process to filter out impurities. So, there's no need to worry about these quartz particles; simply Rinse them out with clean water before using the teapot.

Three: Marks Like Flaws Around the Mouth of the Pot

Some teapot enthusiasts may notice a circle of marks around the mouth of the teapot and the lid that resemble scratches made by sandpaper. The body of the teapot is smooth, but near the mouth, there might be a circle of more or less noticeable scratches. These can be clearly seen when held up to the light and feel slightly rough to the touch. These are often mistaken as defects or signs of a defective product, but this is not the case. This is due to a modern process called “mouth finishing.”

▲ Lid Scratches

During firing, purple clay shrinks. Even if the same clay material is used for both the body and the lid, they will still shrink differently. The degree of shrinkage equals the shrinkage rate multiplied by the shrinkage base, which refers to the length and thickness of the object. Therefore, when making the raw pieces, the lid must be proportionally larger than the mouth.

▲ Lid Mouth Finishing

To master the shrinkage rate, one must study the clay material, although adjustments can only be made based on experience. Different types of clay have different shrinkage rates, and even highly skilled teapot makers face challenges when working with new materials. Therefore: the lid of a purple clay teapot must be slightly larger than the mouth. If the lid is the right size or smaller when raw, then it's unsalvageable, as the gap between the lid and mouth will widen after firing.

Upon discovering these issues, don't panic—you haven't bought a “defective” purple clay teapot!