I felt the same when mum's gold bracelet and necklace went missing. She never took them off (couldn't!) and they did not need to be removed for washing, etc.
Whilst in the care home, mum lost all the usual things - clothes, glasses, etc, and gained a few items that didn't belong to her. That's the way it is... However, the staff know this too... Mum's jewellery could only have been removed by a member of staff, but who can prove that? The manager was horrified and questioned all the staff (which didn't make me very popular!) but there had been several agency staff working in the home over the past several weeks so the blame was put on them.
In the end, it was my fault because I should have removed the jewellery when mum went in there. I'd taken her wedding/engagement rings for safe keeping but that was because they were loose. You just don't expect a vulnerable old person to be robbed but sadly, it does happen sometimes. And let's not forget, our loved ones are in care homes, not in a prison - they should be allowed to keep such things as personal jewellery without fear it will get nicked by opportunistic carers.
Whilst in hospital before the care home, mum 'lost' her gold earrings, her purse (from her handbag) her dentures, 2 pairs of shoes/slippers, and ALL her clothes including a heavy padded jacket. I met her from the ambulance when she arrived at the care home - she was wearing a hospital gown with sick down the front, nothing beneath it, not even knickers, and had a carrier bag with a stale sandwich, an empty handbag and a book in it. So hospitals are no better - probably worse.