I've been wondering about this for a while.

I maybe a little bit neglect to clean up after my salvia plants so every few months their pots are surrounded by dead leaves and the leaves always have this stuff on them when I pick them up.

So what I'm wondering is if anyone else has noticed this and is it safe to use these leaves since I don't know what the stuff is. Here are some pictures - the one that looks like the moon is me trying to use my phone to take a pic through a super old microscope.

I couldn't get a good picture at high magnification but up close they look kind of rectangly and pointy.

I have a ton of these leaves but I don't really want to mess with them if I don't know what this stuff is.

Plants are all indoors, btw.

Are you possibly wondering if that's a crystalline neoclerodane diterpenoid?

It doesn't look like pictures that I've seen of salivnorin a crystals. It would be interesting if it was but scraping all of it off of the leaves would probably be more of a chore than just extracting it chemically.

You only need a little bit for presumptive testing, to eliminate the possibility of it being calcium oxalate or other salts.