Citric Acid can be used to make fizzy bath bombs together with sodium bicarbonate.
It has a texture similar to granulated sugar.
However it also has many other uses including:
Fizzy Bath Melt Recipe (Makes 8 x 30-35g Melts)
120g Sodium Bicarbonate
100g Organic Cocoa Butter
50ml Sweet Almond Oil
60g Citric Acid
8ml Essential Oil (20 drops per bath melt)