How to Tell a Well Set Round Diamond: Where the Prongs Should Sit
By Clint Casmiro, Co-Founder, Smiro Studio, Toronto · Updated October 4, 2026
Short answer: On a well set four prong round diamond, each prong lines up with a corner of the table, the flat facet on top of the stone. Draw a line from one prong across the table and it should run straight to the opposite prong. If the prongs sit off those lines, the stone was set out of alignment and the ring will look slightly crooked from the top.
Check this before you buy a round diamond ring. It takes ten seconds and tells you a lot about how carefully the ring was made.
Read the video transcript
Make sure you notice this before you buy a ring. I'm going to show you how prongs should be set on a round diamond. So this is a round diamond, four prongs. You see how there's the table of the diamond right here? These prongs should be touching the corner of this table, giving you perfect alignment. You can see this prong is running right down this line, this prong is running right down this line. A very well set round diamond.
What is the table of a diamond?
The table is the large flat facet on the top of a round diamond. On a round brilliant it has eight corners. Look straight down at the stone and you will see its outline.
Where should the prongs sit on a round diamond?
With four prongs, each one should touch the stone at a corner of the table, so the four prongs sit at even points around the diamond. Each prong should run straight across the table to the one opposite it. In the video you can see the line from prong to prong running right through the table.
What does a badly set diamond look like?
- Prongs bunched closer together on one side.
- A prong landing in the middle of a table edge instead of a corner.
- The stone tilted, so the table is not level when you look from the side.
- Prongs of different thickness, or tips that do not sit tight against the stone.
Why does prong alignment matter?
Alignment is about more than looks. Even prongs share the load on the stone, and a tilted or off centre diamond puts more pressure on some prongs than others. It is one of the first things we check under the microscope before a ring goes out.
Does the same rule apply to six prongs?
The idea is the same: prongs evenly spaced, matching in size, and lined up with the facet pattern of the stone. Six prongs just divide the circle into six instead of four. See 4 vs 6 prongs on a round.
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How can I check prong alignment without a microscope?
Look straight down at the ring in good light, or zoom in with your phone camera. The table outline and the four prongs are easy to see at that size.
Should prongs touch the diamond?
Yes. Each prong tip should sit tight against the stone with no gap you can see.
How often should prongs be checked?
Once a year, or any time a prong catches on clothing.
How much does a round diamond engagement ring cost?
A fully custom ring from us starts at about $4,000 USD, and most of the rings we build land between $4,000 and $5,000. Our Ready To Order settings start at $1,299 CAD, plus the diamond. The centre stone moves the price most: in September 2026 a 2 carat lab grown diamond ran about $2,500 CAD and a 3 carat about $2,700 CAD. Real numbers are in our cost guide.
What should I check before buying an engagement ring?
Prong alignment, prongs tight to the stone, a level table, even pavé, and a written warranty. Ask to see the ring under magnification.
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