Originally Posted by Alek
Alek, dude, you are good! When I did material analysis and contamination identification, I had to use all sorts of expensive equipment. I'd start with polarized light microscopy and sometimes that was enough to identify the material by size, morphology and behavior under polarized light. But I usually had to use either Fourier-transform infrared spectroscopy or a scanning electron microscope equipped with energy-dispersive X-ray analysis to get a confirmation.
But you're able to tell me what the material trailing the ends of the steel in this photo is not (and presumably is) simply by looking at it! You don't need a sample or even to see it directly, you can just look at a photo!
When my former bosses hear about your abilities they are going to be really, really pissed that I misled them into spending so much money on training and instruments when they could have hired you to just glance at some photos.