What are they?
Answers (1)
You are lucky it didn't blow up in your face. Potassium nitrate and sugar is a low performance rocket fuel. Sulfuric acid attacks sugar, releasing carbon foam. You should investigate the chemistry of any experiment before you do it so you don't get surprises.
www.google.com/search?source=hp&q=sulfuric+acid+and+sugar
www.google.com/search?q=potassium+nitrate+and+sugar
But I don't know what the crystal stuff was