The theory spread so widely that, by the 1990s, mother rocks in Castanheira had become almost completely devoid of baby nodules on the surface level, as people from across Portugal and even abroad travelled here in the hope of obtaining a much-desired “fertility stone”.
“While there obviously isn’t any scientific proof that these stones help couples conceive, it’s curious to note several success stories from those who have obtained these nodules and placed it under their pillows at night,” Sá told me, adding that he was once contacted by a Brazilian woman who reportedly became pregnant after taking a stone from Arouca.
In fact, the Geopark currently has an experimental programme to “rent a Pedra Parideira” for a defined period to couples wanting a baby (interested couples can contact the Geopark to enquire). Although the main reason behind it is to stop people stealing the stones, its introduction has perpetuated the fertility myth.
As I turned to leave the Magic Mountains, the image of the woman in the black cloak came back to me. Whether or not the stories are true, it seems that the mysterious power of the stones continues to live on in this remote region of Portugal.
Geological Marvels is a BBC Travel series that uncovers the fascinating stories behind natural phenomena and reveals their broader importance to our planet.
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