Billiard chalk, commonly known simply as "chalk", is often assumed to be similar in composition to ordinary blackboard chalk. In fact the two are very different. Regular chalk is made mainly of gypsum, while billiard chalk is pressed from a functional composite powder. Its core purpose is to increase the friction coefficient between the cue tip and the cue ball, preventing miscues while protecting the tip. Based on formulation characteristics, it falls into two major categories: dry chalk and oil-based chalk. Their basic mineral components are broadly the same; the difference lies in the binder and additive system. The overall formula consists of mineral fillers, hard abrasive particles, binders, colorants and a small amount of functional additives.

Mineral fillers account for the largest share of raw material in billiard chalk and form the skeleton of its matrix, generally more than 70% of total mass. Common materials include calcium carbonate, talc and diatomite. Calcium carbonate, i.e. fine limestone powder, is widely available and relatively soft, making it the most popular base powder. It gives the chalk moderate adhesion so that a light wipe coats the tip evenly. Talc is soft, and its layered structure improves lubrication and spreadability, giving a smooth application without clumping or scratching the tip. Diatomite is a porous mineral containing many microscopic pores; it absorbs the oils in the formula and its porous structure improves how well the powder clings to the tip, boosting friction. These minerals are blended in proportion — using any one alone makes it hard to balance feel and anti-slip performance.

Hard abrasive particles are the key functional component behind anti-slip performance. They are usually made of silica or alumina powder. Far harder than the mineral fillers, their particle size is finely ground and screened. When we rub chalk onto the tip, these tiny hard particles etch countless microscopic rough grooves in the tip surface, increasing friction between tip and cue ball and reducing the chance of miscue on spin shots. Particle size and dosage must be tightly controlled: overly hard or coarse particles will excessively wear the tip and even scratch the cue ball, while too few particles sharply reduce the anti-slip effect. The difference between grades of chalk largely comes down to the purity and particle-size uniformity of the abrasive. Premium chalk uses ultra-fine high-purity powder that delivers anti-slip performance while minimizing damage to tip and ball.

The binder is the key material that presses all the powder into a solid block, and it is also the core distinction between dry and oil-based chalk. Dry chalk uses water-soluble binders such as resins and cellulose, and contains almost no oil. Once pressed, the finished block has many pores and a loose texture; it sheds a lot of powder when applied and coats quickly, but the dust easily contaminates the table and cue ball, making cleanup a hassle. Oil-based chalk adds mineral or vegetable oil together with resin binders. The oil fills the gaps between powder particles, so the block is dense and compact, sheds little powder, and does not readily soil the cloth. The oil also helps the powder adhere to the tip for longer. The drawback is that if a lot of oil gets onto the cue ball, the surface becomes slippery and actually harms play, so you need to wipe the cue ball frequently when using oil-based chalk.

Colorants and trace additives account for a very small share. Colorants are mostly inorganic mineral pigments used to create blue, green, grey and other colors; inorganic pigments are highly stable and do not fade easily. Some formulas add a small amount of dispersant to help the powders mix evenly and prevent uneven local composition or cracking of the block during pressing.

Formulating billiard chalk means balancing multiple conflicting demands: friction performance, tip wear, powder shedding and application feel. Low-quality chalk uses cheap coarse impurities, which not only performs poorly but also badly scratches cue tips and cloth. Quality chalk balances the proportions of mineral fillers, hard micro-powder and binders to deliver anti-slip performance while minimizing equipment wear. Billiard chalk works purely through physical friction — it does not rely on any chemical reaction with the ball. That is the key to understanding how it works.