Saffron is a spice derived from the flower of Crocus sativus, commonly known as the "saffron crocus". The vivid crimson stigmas and styles, called threads, are collected and dried to be used mainly as a seasoning and colouring agent in food. Saffron, long among the world's most costly spices by weight.
Large quantities of these flowers are required to be harvested in order to yield a viable supply of saffron threads, since each flower only has three stigmas (it takes 50,000- 75,000 flowers to produce one pound of dried saffron threads, equivalent to approximately 20 hours of labor), making the harvesting an extremely labor intensive and time consuming process.
Today, saffron is grown mainly in Spain, Italy, Greece, India and Iran, with the best quality saffron originating from Kashmir. These extremely valuable threads of this red gold (or King of spices as it is also called) have been used for more than 40 centuries by the Persians, Greeks and Romans, and was deemed to be worth its weight in gold.
According to luxury-insider.com