Picks

Finding the perfect pick is sometimes like finding the perfect guitar - you have to try a lot of them until you find the right one! For many, the ultimate material for picks is real tortoise shell, but this material is unavailable because it comes from an endangered species. You'll see many modern picks compared to tortoise shell.

Materials	There is an enormous variety of materials used for picks, and there are new ones coming out all the time. All are composed of man-made materials of some type or another.
Makers	Many Bluegrassers like Clayton Golds, Dunlop Ultex, and Dunlop Tortex. Other picks that are popular are from Wegen and Tortis. The standard cellulose pick like those made by Fender are also a popular choice. A new entry into the pick market is the Blue Chip pick This pick is remarkably like real tortoise shell in the sound it produces, but is man-made and not as brittle. Although expensive by comparison, this pick is truly remarkable in terms of its sound and wear-resistence
Shapes	The most common pick shape is the standard teardrop shape. Some players prefer the larger triangle shape (tri-tip).
Thickness	Bluegrassers tend to use thicker picks than electric guitar players. If you use too thin of a pick, you'll start noticing a clicking sound along with the notes. A pick with a thickness between .8 mm and 1 mm is a good starting point This would fall somewhere around the "medium" or 'heavy" category of some makers. If you want a fatter tone, try a thicker pick. for a thinner tone, go with a thinner pick.
For the ultimate bible on picks, check out Picks! - The Colorful Saga of Vintage Celluloid Guitar Plectrums. This delightful little book by Will Hoover is an illustrated history that has fantastic photos of picks made throughout the years.