Tips and Chalk – Wikipedia

Chalk is applied to the tip of the cue stick, ideally before every shot, to increase the tip’s friction coefficient so that when it impacts the cue ball on a non-centre hit, no miscue occurs.

Leather tips of varying curvature and degrees of hardness are glued to (or in some cases screwed into) the ferrule. The tip end of the cue will vary in diameter but is typically 9–10 mm for Snooker.