Carnotite is a source of what?

Question

What country was the main source of the straw hats which became popular in the 18th and 19th century among gold seekers and work crews on a major canal being dug at the time?

Answer 1

Uranium
Carnotite, also known as yellow cake, is a hydrated vanadate of uranium, potassium, and small amounts of calcium, barium, magnesium, iron, and sodium. It is mined for uranium and at times in the early 20th century was mined for radium or vanadium. It is named for Marie Adolphe Carnot (1839–1920), a French mining engineer and chemist,