I paid about $120 on ebay. They were described as Georgian, handmade, using old-cut mined diamonds set into solid silver 800 with original 9ct gold clasps. I think I got a great deal on them since they look a lot like these which are on sale for $950.
And these, which are$600 on Ruby Lane:
Then I went over to Gloria's to hang out and work on some costume stuff and she has this book on Georgian jewelry:
In it are some examples of Georgian earrings, I believe 1780s, that have similar hooks and similar mounting of the diamonds. We both decided that the hooks look original to the earrings.
I looked up how to clean them and one site suggested baking soda and water for silver. I used a really really soft bristle toothbrush - I didn't want to scratch the silver, but the holes in the design were completely filled with dirt and the brush helped poke them open and also get off some of the hardpacked gunk on the back of the earrings.
They look so much better now! Here are some before and after pics.
And the auction pictures: