Saffron is the little thread at the center of a small purple crocus, where the pollen catches and develops. There are a whopping three threads per flower, which are hand-picked and then dried. That, and the fact that it takes 13,125 threads to make an ounce is why saffron is the world’s most expensive spice.
The good news is that saffron has such a pungent, spicy flavor, that it takes only a small amount to add flavor and color to a dish. It is an essential ingredient in the French bouillabaisse, in many Spanish paellas, Italian risottos, Portuguese rice dishes, Persian pilafs, and Indian biryanis.
Saffron is sold in threads, and also, as you have seen it, in powdered form. Saffron threads should be ground or crushed before you use them in a recipe, but they have two advantages over pre-ground saffron. First, saffron begins to lose its potency once ground, and there’s nothing worse than flavorless powder that you mortgaged your house to buy. Also, powdered saffron can be diluted with either turmeric or ground safflower by nefarious spice merchants without you being the wiser.
You can certainly substitute a teensy amount of ground saffron for a teensy number of saffron threads.