Boric Acid H3BO3 Industrial Grade - Minimum 99.9% Purity Industrial Grade - Minimum 99.9% Purity Granular boric acid is more dense, much like salt crystals. Powder boric acid is very fine. There are many uses of boric acid. Here are some examples: pH adjustment (pools) a way to fireproof fabrics flux additive use to add life to tools steel hardening preservative for many materials eyewash ointments