Question
Thanks very much for your help.  Great idea to try dissolving the "crystals" in both water and alcohol.  I did that and got no reaction at all to either.  (So salt and sugar are both out.)  It doesn't look like paint or other chipping, it's too uniform, and too "sparkly," like salt or sugar would be.  But the very strange thing is that I'm finding this again and again in the back bottom of a closed desk drawer.  Something might have fallen into the drawer while it was open once or twice, but this is happening routinely.  That's why I thought insects, since I can't imagine what else would be getting in there.  At least I'm glad that you don't think it's insects, since my primary concern was that I had an infestation that was going to spread through the apartment if I didn't do something.  Thank you very much for reassuring me on that point.

Now I'm thoroughly confused about what this might be.  I wish there were someone with a microscope and expertise I could send this to who might be able to recognize it.  I'll get myself a good magnifying glass sometime and look more closely.  Meanwhile, I'll pretend it must be a trick by tiny poltergeists, and hope they're friendly.

Thank you very much.  And if you do have any other ideas, I'm all ears.

Answer
I agree, very strange. Definitely collect some of this material in a vial so that it can be looked at when you find a lab that takes these samples. You might check with your local Cooperative Extension (www.extension.org) as they can put you in touch with a local university. Cornell is the school in NY with the entomology department (and lots of microscopes). Good luck. Sorry I can't be more specific.

Jack DeAngelis