Today’s blog is all about our favorite glittering, gleaming, light-catching gem: diamonds! Specifically, the anatomy or the parts of a round brilliant diamonds, the most popular cut of all.

From the top to the tip, we’re explaining every part, portion and proportion of a diamond anatomy's - every part that makes a stone either seriously sparkling or drab and dull. Every one of these sections plays a role in a diamond’s cut grade, and ultimately, it’s level of brilliance, fire, and sparkle.

This is part 2 of our ‘Learn to Speak Jeweler’ series. Read our ‘Anatomy of an Engagement Ring’ post for more terms & tips on jewelry buying. Plus, visit our blog, Diamond Cut: Our Favorite of the 4Cs to dive even deeper into diamond selection!

Diamond anatomy and Parts explainedCrown Of A Diamond

Just as you’d wear a crown on your head, a diamond crown is upper portion - the topmost section of the stone. It includes everything that sits above the diamond ‘girdle’.

When light passes through the crown, it's reflected back from the pavilion (base) to the viewer’s eyes. All the diamond facets reflect light in different directions for a multifaceted light show.

CROWN HEIGHT

The crown height affects a diamond’s brightness and fire (the amount of colored light reflected out of the stone).

CROWN ANGLE

The angle from the top of the girdle to the diamond table (flat top). This angle affects a diamond’s brilliance and fire from the top view. A well-cut diamond will have a crown angle between 31.5 to 36.5 degrees (you’ll find these measurements on all GIA grading reports).

Girdle Of A Diamond

The middle portion of the diamond that separates the crown and pavilion (base). A well-cut diamond has a goldilocks girdle – not too thin and not too thick for that specific diamond. A too thin girdle can risk chipping, while an overly thick girdle puts too much weight in the middle of the diamond, making it appearing smaller than diamonds of comparable carat weight.

If the girdle thickness is off, a diamond can only receive a maximum Very Good GIA cut rating regardless of all other factors. The ideal diamond girdle rating is thin-medium, and slightly thick-thick is considered an excellent to ideal proportion.

Lower Girdle / Half Facet Length: the measure of the lower girdle facets in relation to the pavilion Basically, this controls the contrast and brilliance of a diamond. Well-cut diamonds will range between 65-90%.

Pavilion Of A Diamond

The lower portion of the diamond that starts at the girdle and ends at the culet (pointed base). Most of the diamond weight is in the pavilion.

PAVILION DEPTH

Another goldilocks measurement, a too ‘deep’ or too ‘shallow’ pavilion allows light to exit through the sides or bottom of the stone, creating a dull, lifeless looking diamond. A well-cut diamond allows light to reflect through the top of the stone, creating a brilliant, luminous sparkle.

PAVILION ANGLE

Ok, get ready for geometry class – this is “the average of the angles formed by the diamond’s pavilion main facets and its girdle plane”. What you need to know: an excellent cut diamond will have a pavilion angle between 40.6 and 41.8 degrees and will sparkle with gleaming brightness.

Table Of A Diamond

The flat, topmost (and largest) facet of the diamond – what you see from a bird’s eye view. The diamond table refracts (bends) incoming light rays which are then reflected back from the pavilion into the observer’s eyes.

TABLE SIZE

The table size is measured in relation to the girdle diameter. An excellent grade diamond has a table size of 52 to 62 percent, along with all the other corresponding dimensions and proportions that make up a well-cut diamond.

total Depth Of A Diamond

The overall height of a diamond or gemstone measured from table to culet – this is measured as a percentage of the girdle diameter. Diamonds graded from Very good to Ideal have a depth of 54 to 66 percent.

Culet Of A Diamond

The small pointed facet at the base of the diamond. It’s sized as none, very small, small, medium, slightly large, large, very large, or extremely large.

Excellent cut diamonds will fall into the ‘none to small’ range, which means the culet is not visible to the naked eye. Larger culets are less desirable as they allow light to escape through the bottom of the diamond.

This 'smaller-is-better' motto applies mostly to modern cut diamonds. Old cut diamonds had much larger culets which draw your eye into the stone and have their own unique beauty.

Your diamond anatomy questions answered

What are the parts of a diamond?

The five main parts of a diamond are the table, crown, pavillion, girdle, and culet. Scroll up for explanation on what each of these parts are and how to choose the right proportions for each!

what is the pointy part of a diamond called?

The pointy base at the bottom of the diamond is called a culet. Scroll up for how to pick the perfect culet proportions for your diamond!

What is a pavilion on a diamond?

The diamond pavilion is the bottom part of the diamond - the V-shape, pyramid-esque section that sits below the girdle.

For more diamond pro-tips & tricks, visit our blog! And as always, use these terms and measurements as a guideline, but more importantly, listen to your intuition when picking diamonds and gemstones (and always consult with an expert jeweler if you're unsure). Just like choosing your partner, good-on-paper is great, but it’s nowhere near the whole picture!

For diamond or jewelry-related questions of any kind, send us a message anytime or book a free virtual consultation – we’re always here to chat about our favorite topic!