Perhaps this one is actually a toadstool (for a very tiny toad).
Or maybe a flying saucer.
I did a spore print - the colour is dark browny-purply-black.
I spent ages searching Roger Phillips' book for this and a few others I've found recently. Identifying fungi is SO difficult! It seems to fit the description for Panaeolus rickenii. It *looks* like lots of others, but spore print colour narrows down the options. Whatever it is, it's very pretty. And no, I'm not going to eat it.