1. The true identity of super phosphate is its hard granules and brownish colour.
2. Heat some of the granules of Super Phosphate, if they do not grow, then understand that this is the real super phosphate. Always keep in mind that other complexes and DAP granules increase their size on heating while Super Phosphate granules remain same in size.
3. Superphosphate cannot be broken with nails. So, mostly there are chances of adulteration by mixing DAP and NPK.