The stigmas from a small purple crocus (crocus sativus). Each flower only contains three of the yellow orange stigmas that must be hand picked, making saffron the world's most expensive spice.Thankfully a little saffron goes a long way and you need very little in a recipe. Saffron is a pungent, aromatic, and earthy flavored spice that gives everything cooked with it a brilliant yellow tint.