The first two numbers represent the outside diameter of the diamond as taken from a direction of North to South and East to West the third number is the depth of the diamond as measured from the top of the table facet down through the stone to the bottom point which is the culet. The numbers will be in relationship to one another, but you needn't pay the last number too much attention. Assuming this is a round stone, you want the first two numbers to be relatively close to each other and certainly within 10/100ths to maintain a round look to the stone... Then focus on the total depth % measurement which should be within 59 - 61.8% to achieve a nice balance between the weight of the stone and what you see visually in terms of spread.