QUESTIONWould you please advise what is the best caulking to use between tile backsplash and granite counter?
ANSWERANSWER - You should use an ASTM C920 silicone sealant suitable for granite.
Laticrete has a product called Latasil that comes in many colors.
Dow Corning has a product called 795 or 790 that comes in a variety of colors and they say it is suitable for most stones. Make sure that the sealant is compatible with your stone. Some sealants can stain some stones.
Be sure to follow the manufacturer’s directions that require cleaning the joint out, using a primer, and putting in polyethylene foam backer rod or tape so that you have at least a 1/4" thick sealant depth.
With silicone sealants you need to use blue masking tape along the edges and immediately after the sealant has been applied and tooled, you need to carefully pull the tape. This will give you a nice straight and clean joint.