I have been running cargo missions for five days now and not seen one. That is my point. Exquisite crystal - got those.
Which systems have you been getting them
Pretty consistently for the past couple of weeks I have been running cargo and data delivery missions out of Haller City, Barnard's Star to the neighboring systems to grind FED rank, mostly to Epsilon Indi & Duamta but moving around a lot in the local area. To break the monotony I do some bouncing back-and-forth data delivery and (FED) donation missions between New Dawn (Ceos) and Newholm (Sothis) while stacking long-range cargo delivery missions back to the bubble. I am constantly throwing out or selling odd tons of materials I keep finding taking up space in the hold, including modular terminals in fact, a bunch of Engineer materials show up in my hold on a regular basis, I am simply not grinding Engineers, presently.
I find that if I fixate on a single goal then I become more susceptible to frustration. If I relax and work my way through the
several goals I am currently working on (presently Credits, FED rank and a Fed Corvette) the credits, materials, etc. just seem to flow. The results: 500 hours played, over 600 million credits liquid and several fully A-rated ships. Not a bad return, a couple of million credits per hour.