Victorian children's (possibly) book about a man who is visited by a bunch of miniature people
Looking for a Victorian-era children's story/novel I read as a child, possibly a short story within a larger collection.
The protagonist is an adult man who finds an object (I believe it was a gold plate or disc) near a stream or brook. After this discovery, small creatures (I thought of them as imps, but they may be described differently—some kind of miniature people) begin visiting him at his home. There is also a black mist??? involved at some point???
Eventually he befriends these small beings, and the story culminates in him travelling to or discovering the miniature town or settlement where they live.
There may have also been an element of memory loss or enchantment involved.
I was reading it alongside George MacDonald and Frances Hodgson Burnett, plus some other Victorian children's books, so the language and era felt consistent with that era, likely published somewhere between 1860 and 1910.
I don't know if it was a standalone novel, a novella, or a short story within a collection or annual.
The details are a bit murky to me, since I read this long ago as a child, but any help would be much appreciated!!!