In the past, we used the four C’s of a diamond to define its quality.
Cut – better knows as shape. This can be round, emerald, Asscher, heart or any other fancy shape.
Carat – carat weight of a diamond
Color – color of a diamond, or better the colorless grade.
Clarity – how clear the diamond is internally. Often natural diamonds have slight inclusions or dots inside, which make them less valuable.
But later there was need for more definition.
Cut Grade was added for round diamonds. represents how well the diamond was cut and polished.
I would add
Country – if the diamond is not in your country and you have to add time, shipping, insurance and import duties, you can’t compare this to a diamond at your local jeweler store.