Did some more experimenting...
I reformatted, into Fat32 again. Still doesn't recognize it.
Had a friend try it on his Samsung Galaxy S3- he gets a "Damaged USB" message.
That's when I noticed that I'm only showing 29.4Gb instead of 32Gb, even when freshly formatted with no bloatware, etc
I assume it's my luck- I've once againt purchased a one-in-a-million damaged/defective product.
I'll see if I can't get Lexar to send me a new one...