Aaand it is time for the reveal! It's a small block of injection molded ABS with a pad printed layer. Or: a yellow #lego brick with the letter W.
Four people figured it out. Thanks for not spoiling it for others. First was @mattdawhit who somehow figured it out without any real hints. Also 馃憤 to James, @CiaraNi & @cazmockett
This one was fun. Thanks for all the excellent comments. I'll post a new one later today and will use the hashtag #MicroGuessr
Apologies for the reminder poll. It reset..
10/x Here's another fun #MicroGuessr microscopic image!
This one is at 75x magnification. Illuminated from the top in true color.
No idea if this one is difficult. If you're absolutely certain of the answer send a DM to keep it fun for others. And feel free to ask questions 馃槃
I'll again follow this post with a "reminder poll" and this time will release the answer in one day.