Stone Dust: What It Is, Uses, and Where to Buy It - The Spruce
The machine has a screen that traps the larger material (that is, the crushed stone). The smaller material or "screenings" falls through the screen. Depending on the size of the holes in the screen used, it can be so fine in texture that it is basically a powder. This is what you are buying as "stone dust." But it may go by other names, such as: