Understanding Crazing

Crazing is a fine network of cracks in the glaze. Crackle occurs naturally when the glaze and the body expand or contract at differing rates during the cooling process. Manufacturers of fakes often intentionally crackle pottery to make it appear older than it really is by throwing open the lid of the kiln while the newly fired pottery is still hot. Real crazing becomes discolored with use due to grease seeping in to the cracks. In order to try and mimic this effect, fake pottery is often rubbed down with Old English Furniture polish to discolor the intentional cracks. In the pictures below you can see real crazing. It is not uniform, is darker in some areas, and is UNDER the glaze on the bottom. Remember, the grease seeps from inside the jar out. Fake items are discolored from the outside of the jar in. This makes for a very different final effect.

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Real Crazing. Notice the crazing is INSIDE the jar, and has darker and lighter irregular areas.

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Real Staining from use. Notice that the white glaze from this McCoy mammy is over the discoloration. That's because the grease stains came from inside the jar.

Fake crazing

Fake Crazing

Notice the absolutely uniform "crazing" inside and out

Notice the top of the jar. How would grease stains get in the inside of the top of a cookie jar?

Notice the rim on the inside of the top. The furniture polish has darkened it uniformly all the way around. Use and time do not do this so evenly.

Notice the EXTREME crazing, yet on this piece, the cold paint was pristine. Extreme crazing from use and perfect cold paint are not consistent with real age.

Remember, crazing is NOT a function of age. Brand new pottery is often crazed. It is the discoloration of the crazing that can come from time and use, but it can be "faked". Judge a crazed piece with common sense. Does the discoloration on the jar look like what you expect from use, or does it seem too consistent to be real?