How do you buy a diamond like a professional? It cannot be stressed enough that you must be very careful when purchasing for diamonds.  You should check the background and authenticity of the diamond seller.How to buy a diamond? One very important tip in buying diamonds is to ask for a diamond certificate from the jewelers.  With diamond certificate, you are assured that what you bought or what you are buying are certainly worth exactly what the jewelers claimed them to be.  A diamond certificate is the blueprint of a diamond.  It tells the exact measurement, weight and the details of the cut and quality of the diamond. In short, it speaks out all the individual properties of the stone itself and gives proof of the diamonds’ identity and value.  Some sellers may ask for a little pay for the diamond certificate but its cost is usually quite low.  Securing a diamond certificate will provide a much-needed peace of mind knowing that you are getting your money’s worth.