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Diamond Anatomy

Purchasing a diamond is one of the most exciting and expensive investments you will make so it is best to educate yourself about the physical properties of a diamond, particularly the anatomy. As your knowledge about the physical attributes of a diamond grows, so does your ability to purchase the best possible diamond as well as stay within your budget.

Key attribute summary of a diamond's anatomy.

  • Diameter: The diameter is the width of the diamond as measured through the girdle.
  • Table: The table is the flat facet on the top of the diamond. It is usually the largest facet on a cut diamond. The table also plays a role in determining sparkle and fire.
  • Table Percentage: The table percentage is the value which corresponds to how the diameter of the table facet compares to the diameter of the entire diamond. For example, a stone that has 50% table has a table which is a 50% as wide as the diameter of the diamond. In terms of finding the table percentage of a round stone, gemologists usually calculate the table percentage by dividing the diameter of the table by the average girdle diameter.
  • Crown: The crown is the upper part of the diamond that lies above the girdle. The crown determines the scintillation, or sparkle of the diamond, as well as the fire, or dispersion.
  • Girdle: The girdle is the outer edge and the widest part around the diamond. The girdle forms a band around the stone and protects it from chipping. At times, the girdle could be too thick and add unnecessary weight to the stone.
  • Pavilion: The pavilion lies at the bottom part of the diamond, below the girdle. It plays the most important role in determining the brilliance.
  • Culet: The culet is the final facet to be polished on the diamond. It is a tiny final facet that diamond cutters often add at the bottom of the diamond's pavilion. The purpose of the culet is to protect the tip of the pavilion from being damaged. After the diamond is set in jewelry, the actual setting provides the pavilion with enough protection. However, modern shapes rarely have a culet at all, or a very small one.
  • Depth: The depth refers to the height of the stone from the culet to the table. It is usually measured in millimeters.
  • Facet: The facets are the flat, smooth faces on the surface of the diamond. A facet allows light to enter the diamond as well as reflect off its surfaces from the different angles. They aid in creating the different colors and light that diamonds are known for.

Interactive Diamond Anatomy Chart

More Diamond Attributes to Consider

  • Polish: Polish affects how light is able to pass through a diamond and is very important to a diamond's brilliance. You should only select a diamond that is laboratory certified with good, very good or excellent polish.
  • Symmetry: Symmetry is an important element of a diamond's finish. Symmetry refers to the size, alignment, and matching of the individual facets. You should only select a diamond that is laboratory certified with good, very good or excellent symmetry.
  • Fluorescence: When stones are exposed to long periods of ultra-violet light, fluorescence is a quality that some diamonds acquire. This fluorescent light is not detectable to the naked eye, however if a diamonds attains natural fluorescence it will emit a soft glow when it is held under an ultraviolet lamp. It is not dangerous for a stone to be fluorescent; in fact, it is a unique quality that occurs naturally.
  • Spread: Spread is how large the diamond appears to the naked eye. You can figure out the diamond's spread by dividing the 'depth' by the table 'diameter' and multiply by 100, this gives you the depth perentage. A good depth perentage is based on the table and is between 56% and 62.5%. Girdle thickness and crown and pavilion angles affect the spread as well.