The story
From phospho- + walpurgite.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A triclinic-pinacoidal brownish gray mineral containing arsenic, bismuth, calcium, copper, hydrogen, iron, lead, oxygen, phosphorus, silicon, uranium, and vanadium. Full definition →
From phospho- + walpurgite.
Etymology from Wiktionary, CC BY-SA 4.0.