It can be a real challenge Bill, unless you have distinct crystals, very rare for hawleyite. They are in different crystal systems, hexagonal for greenockite, isometric for hawleyite. But many occurrences are just yellow powdery coatings. In this case, the answer is no.
Is there an ‘easy’ way of telling greenockite from hawleyite?
It can be a real challenge Bill, unless you have distinct crystals, very rare for hawleyite. They are in different crystal systems, hexagonal for greenockite, isometric for hawleyite. But many occurrences are just yellow powdery coatings. In this case, the answer is no.
Got a pic in natural light?
https://www.mindat.org/photo-1149529.html