“Ramina” is what we name it in center Italy, the traditional glaze, the one that was used to mark vases. Marks were made to recognize their destination, Appignà, Recanti, Montefà, before loading them on a chariot. The old age of fifty years ago when water wasn’t arrived yet. Water was not in houses, it was running but in river streams. Pottery was vital, until people found the longevity of plastic. Plastic doesn’t keep fresh the water, potter’s answer.
“Ramina” is CuO, copper oxide, the most used is the black one, Master Testa used to go and collect it from anchors at the dock when he was a kid. CuO2 reacts differently if combined with different glazes, so it does if mixed with Copper Sulfate CuSO4.
CuO is where I come from, is the land of hills where animals walk in the streets at night.