First, let me say, thanks for picking a mechanic I designed for this contest.
I think there are some interesting designs in this thread, and also some good feedback on the overall concept.
In the original thread where I had posted this, I had added some of my own commentary at the time:
One challenge with the Jewelry mechanic (and any new mechanic, of course) is making sure that the same or similar effect can't be equally or more effectively achieved with existing mechanics.
A regular treasure with a "while this is in play, cards that share a type with cards you've bought this turn cost $1 less", while not the same, might be similar enough to what Bracelet is trying to do.
Hmm, now I'm wondering about the other cards:
Earrings compares to a regular treasure that said "When you play this, the next time you buy a card this turn, +$2 and gain a silver.", but that's different enough - you'd be able to spend the first $2 on the first buy and then get the $2 (and silver). Earrings on the other hand is one or the other - play it first for the $2 with no bonus, or buy something without it, then get all $4. So it feels like a good use of the mechanic, I think.
(though I might still remove the "then play any number of treasures" , just letting you play the silver. And have a new card with
+ Cards based on cards you've bought and then play any number of treasures...)
Ring (as a hybrid Treasure - Night type mechanic) and Necklace (limitation only if you play as a regular treasure) also show that there's some versatility for this mechanic.
So I agree that, one of the challenges of this mechanic is the design space - you need just the right mix for it to not just be a Treasure card or a Night card. Personally, I think Treasure-Jewelry makes the most sense, since part of what I think made these special is the tension between playing it at the start of your buy phase for the $ and having to wait until you've bought something first, reducing the amount you have for one big purchase.
The other thing I tried to do in order to make (some of) my designs be different from Night is to allow them to play Treasures that you gained (Earrings letting you play the Silver) or drew in your buy phase (Jewelry Box letting you play any Treasures from your hand).
One good thing that have changed since I originally posted these is that official Treasures no longer specify "when you play this" on Treasures, so that's a nice cleanup (as we can see with this week's entries).