Granite dust

Granite dust (or granite stone meal) is a garden fertilizer made from crushed granite. It is a natural source of potash. Due to its high concentration of potash, it is a viable alternative to other alkaline potassium compounds such as sulfate of potash, nitrate of potash, carbonate of potash, and ash. The primary potash-bearing minerals in granite dust are feldspars and micas. It can be strewn by hand or by seed cart to form a top dressing. Granite dust has been used in tobacco production since at least the 1950s.