Dip your scrub brush in bleach. Scrub all around the joint where the faucet meets the granite surface. Rinse it and let it dry.
Set the caulk tube in the caulk gun, putting the back end in first and then snapping in the front.
Cut off the end of the tube with a razor knife, making a diagonal cut that’s about an 1/8 inch wide. Slide a long nail into the hole to break the seal inside.
Set the tip of the caulk tube onto the joint where the faucet meets the granite. Compress the trigger to push the caulk up to the hole at the end of the tube.
Move the gun around the perimeter of the faucet as the caulk comes out, laying a smooth, even line over the joint between the faucet base and the granite. Go all the way around the faucet.
Wet your thumb. Press it against the joint between the faucet and the granite. Smooth the caulk down, running your thumb over that joint all the way around.