What are the most common varieties of saffron?

• Sargol: In Farsi, it means "Top of the flower" which derives from the very tip of the saffron thread. It has a specific, powerful aroma more than other types. It is also known as high quality since it does not contain any Yellow or Orange threads. However, during the harvest, and separation process, Sargol saffron often contains crumbs and broken threads.
• Super Negin: This type is the most expensive but rare trim of saffron. It is known not only for its most potent but also for its aesthetically pleasing features. Super Negin threads are longer and contain no yellow or orange threads. The threads are cut symmetrically and contain no crumbs. When comparing all the trims of saffron, Super Negin is the best considering the quality, color, and taste.
• Negin: This type of saffron is longer in length but contains some yellow and orange portions. However, the aroma, quality, and purity are still great but the color is not perfect due to some portions of yellow and orange threads, which makes this type less quality than others.
• Poshal: The cheapest and least quality type of saffron is known as Poshal. This saffron is from yellow parts of the stigma which contains no value, taste, and aroma.

Source: Persian Saffron; the Red-Gold Ingredient