Buying a diamond is a very difficult task for most people. It takes many hours of training for us in the jewelry industry to learn to grade a diamond accurately. How, then, can a person who has not had this training buy intelligently?
People often come into our store and ask for a diamond of a certain grade. They have read a magazine article or been told by someone which grade to buy and what it should cost. This might work if every diamond was precisely graded. This is not the real situation.
Even if the grading is accurate, there is room for a lot of variation in each grade. If you were to buy a basket of apples, all graded AA, you could look through the container and find some you considered better than others. The same is true of diamonds. You must look at the diamond under magnification. A diamond microscope with dark field illumination is ideal for this. You can then see that one diamond looks better than the other. You are not relying upon someone else to judge the stone.
Is the grading accurate? If the diamond has a certificate from the Gemological Institute of America, you are pretty safe. They are usually quite accurate. Some of the other labs may give higher grades.
The accuracy of grading by jewelers varies greatly. Some have staff members trained by the GIA and will grade to GIA standards. Others develop this skill from years of experience. Many have had poor or little training and are doing a lot of guesswork. Some deliberately fudge the grade up a little to make the sale.
Many people buy only by the color and clarity grades. They ignore the important factor of proportion. This can affect the price by as much as 40%. If you have seen a diamond that lacks sparkle, chances are that it had poor proportion.
Be sure to look at the diamond you are buying under a microscope. Our gemologists, trained by the GIA, will show you what to look for. Then, whether you buy from us or someone else, you will be able to make an intelligent selection.