Wearing a diamond is considered special like wearing gold jewelry. It can create certain good vibes in our bodies but it is not compulsory to wear diamonds.
For example, some men wear diamond studs; they cannot be deciphered as ostentatious. It can be worn without ostentation. But if the stone possesses certain defects, it might affect the wearer or his family. One has to select the stone without defects through well-acquainted persons.
It can be worn in an auspicious manner, which is considered better as our people do not wear it for flamboyance.