yana-urca

These garnets re-appear in the trachytic porphyries that crown the celebrated metalliferous mountain of Potosi, and in the black and pyroxenic masses of the small volcano of Yana-Urca, at the back of Chimborazo.

Alexander von Humboldt - Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 3