What is lemnian earth?

Lemnian earth is a reddish earth found in the island of Lemnos, celebrated as a remedy for snake-bites and various diseases, and collected by the ancients in accordance with special religious observances on only one day in the year. Analysis shows it to be composed of silica, 67 percent; alumina, 14 percent; water, 8 percent; iron oxide, 5 or 6 percent; soda, about 3 percent and traces of lime and mag¬nesia. Its classical name "terra sigillata" (sealed earth) is due to the fact that it was compressed and marked with the head of the Lemnian Diana. The earth is a fair substituto for soap, but has no medicinal properties.