It is a tradition in our society that the money a man pays for the bride at the engagement time (Mahr) is used by her to buy different things for her, including gold. Do I have the right to interfere with things my future wife buys, or is it absolutely her right to spend all the money or keep part of it?
Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
A woman has full control over her property, so a husband cannot prevent his wife from acting according to her free choice in her property as long as there is no violation to the rulings of Shari'a.
Therefore, whatever a man gives a woman it becomes her property and she can manage it freely within lawful limits. There is no exception in the above ruling. The same ruling applies to the presents offered by a man after proposal, before marriage or at the time of marriage.
Allah knows best.