Cartier have been doing a 'symbol pendant' charm in yg for years. I have the original on a charm bracelet but not the diamond version. Mine was a gift. I think the Cartier versions are perfect for gifts. I also think Cartier chains are not bad value wise, so if you get it and want to wear around your neck, I'd recommended chain to go with it.
The Carter diamond version is very small. There are many brands that have similar, Dubai is literally full of them, many of them at a better price-point. If you like ME inspired jewellery that is of excellent quality you could also look at the Tabbah's Talisman collection
FYI, it's a cross-cultural amulet. The 'hand of Fatima' amulet was called the 'Hand of Miriam' in biblical (pre-Islamic) times and still is among older religions. Named after the sister of Moses, Miriam protected her baby brother from otherwise certain death. 'Hamsa' as strength against the negative forces of others goes back even beyond Abrahamic religions (as you can tell from teachings in Judaism and Islam that no graven images should adorn). Thought to originate from Ancient Mesopotamia. It's has remained a protection against the evil eye (with or without an eye in the centre of the palm Nazar) and more lately links with the maternal.