This is a slug of Grolleg porcelain that is about 1 year old. When pugged it was perfect homogeneous white. These streaks and specks have all developed over time as it ages. A slice of this cross section fires pure white.
Ceramic glazes and clay bodies can host micro organisms. They can be just a nuisance, a source of worry or they can render a product useless. What should you do?
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