All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
According to the correct opinion of the jurists and the view of the majority of the scholars, may Allaah have mercy upon all of them, it is an obligation to pay Zakah on the money (or wealth) of the child if it meets the conditions of paying Zakah. This is whether the money which the child obtained is a gift, or inheritance or else, and whether the money is cash money, or gold and silver, or other items that are liable for Zakah. It is an obligation to pay Zakah on all of them if the conditions (of paying Zakah) are met. Moreover, it is the guardian of the child who should pay the Zakah on his behalf.
For more benefit, please refer to Fatwa 85400.
Finally, it should be noted that according to the view of the majority of the scholars there is no Zakah at all on the jewelry that is prepared for permissible use.
For more benefit, please refer to Fatwa 83665.
Allaah Knows best.