Kea, Cyclades is a small island that enjoyed considerable prosperity from the Bronze Age to the Hellenistic period: in the 6th century, despite its small size, the island was home to four separate city-states. Kea had good agricultural soil, but the richness of its mineral deposits, including miltos (fine iron oxides) was a likely factor adding to the island's prosperity. Miltos was primarily used as a pigment but also had medicinal applications. Kean miltos was highly valued. A 4th c treaty between Athens and Kea's individual city states prohibited the sale of the product anywhere other than to Athens. The Tetrabiblion, a medical encyclopaedia compiled by Aetius Amidenus in the 6th century AD, recorded that the Kean miltos was astringent and a drying agent and could also be applied around the eyes to stop watering. When taken in a drink, miltos could be used to stop the spitting of blood.
The Fe-rich Orkos mines worked in the 19th century are thought to have oblitarated any earlier mining activity but other ancient galleries, presently inaccessible, may still retain evidence of G-R activities.
images clockwise from top: Orkos looking east;map of Kea showing four city states etsablished by the 6th c. BC; Orkos gallery; miltos specimen; view of Orkos gallery entrance on a precipitous cliff (images Effie Photos-Jones).