One of the most common questions buyers ask is: should calcium carbonate be selected by mesh size or by micron-based particle size? The answer depends largely on whether you are using GCC or PCC.

For GCC (Ground Calcium Carbonate), mesh size is still widely used in the industry. Typical grades include 325, 400, 800, 1000, and 1500 mesh, which roughly correspond to particle sizes from tens of microns down to around 10 microns. Mesh classification works reasonably well for GCC because it is produced through grinding and air classification.

However, mesh size is only an approximate indicator. For finer GCC grades above 1250 mesh, manufacturers increasingly provide laser particle size distribution data, such as D50 and D97, to ensure consistency and performance.

For PCC (Precipitated Calcium Carbonate), mesh size is generally not used at all. PCC particles are much finer and more uniform, often with D50 values between 0.8 and 3 microns. Because PCC particles are formed chemically rather than mechanically, micron-based measurement is the only accurate way to describe their size.

In applications such as paper coating, high-gloss paints, and engineering plastics, micron-level control is critical. Even small differences in particle size can affect opacity, rheology, and surface finish.

In conclusion, mesh size is practical for standard GCC selection, while micron-based particle size (D50/D97) is essential for PCC and high-end applications. Understanding this distinction helps buyers avoid specification errors and ensures stable product performance.