The wishing stars only give flow. However if you are a resident a new update coming on the 31st may will give you keys. The possible rewards are gems or a wishing star.
Whishing stars acctually do not only give flow anymore you wish for stuff!!! My only problem is whenever I get a key I always get the box :(
now go enjoy a nice cold soda :D
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now go enjoy a nice cold soda :D