The person who advised on the gemstone should ideally have knowledge of the correct vidhi which must be performed. All I can say is to get a second opinion of the gemstone- it should be matched to your particular astrological chart- which will also ascertain the correct fitting of the diamond (in gold, silver or copper). The diamond itself must be cleansed in the correct way. You will also have to be presented with the diamond and wear it for the first time on a particular day which will be determined by astrological charts.