Shears are a tool used for obtaining Wool, Ferns, Tall grass, mushrooms (from a Mooshroom), Leaves, Vines, All flowers from 1.7.2, and cobwebs, which will drop string. If it is enchanted with Silk Touch, it will drop the actual cobweb.
To obtain wool, a player must right-click on a sheep with the shears and the sheep will drop 1–3 blocks of its corresponding color of Wool. It won't damage the sheep, but it will change the sheep's texture to give it a sheared look. Wool cannot be harvested from a sheared sheep until it turns a Grass Block into a dirt block (and grows back its Wool). Its appearance will change back to normal when the wool has grown back.
Shears are strong and will last for a long time. It can obtain leaves as a regular block, instead of completely destroying it, and Vines that will act as Ladders instead of building those, allowing players to preserve their resources for more valuable products. Shepherd Villagers will sell shears for Emeralds.