Several lab-grown white diamonds with their own anatomy & structure.

Anatomy of a Diamond: What to Know Before You Buy

All diamonds, whether mined from the earth’s crust or created in a laboratory, start as rough-looking stones with a glassy appearance. They don’t become the brilliant, glittering gemstones we’re all familiar with until the art and science of cutting is performed by a highly skilled technician.

Crafting these gems is based on the individual anatomy of each diamond. See what you need to know before you buy your diamond engagement ring or wedding bands.

Anatomy of a Diamond

Whether a diamond is pried from the earth’s crust or created in a laboratory, they have the same basic structure. All diamonds are crystals — carbon-based crystals. These precious stones were formed through immense heat and pressure forces deep within the earth over millions of years. In comparison,  synthetic or lab-created diamonds may take only a few weeks. Laboratory-created diamonds are also subjected to intense pressure and heat conditions and develop the same crystal structure as natural mined diamonds.  

Diamond crystals can form many different shapes, but the most common profile is the one we’re all most familiar with – an eight-sided octahedron. The diamond structure allows crystals to be perfectly split along cleavage lines, preventing shattering into unwanted pieces. This property of diamonds enables cutters to shape and facet them into sparkling gemstones. Accidents can happen, though, and while diamonds are incredibly hard, they can be brittle and shatter if the split along the cleavage line is poorly done.

Cutting and Shaping Diamonds

Cutting and shaping rough diamonds are two different but related processes. Cutting refers to the faceting of the stone—creating multiple flat angled surfaces around the entire shape of the stone. Facets are cut to maximize the capture and reflection of light in and by the diamond. Cutting in this manner creates the famous sparkle that diamonds are prized for.Chart of Diamond Shapes

Popular diamond designs include Heart, Oval, Pear, and Princess. By far the most popular, however, is the Round Brilliant shape which dominates the market. Round Brilliant diamonds have 58 facets cut into them, giving the highest brilliance and fire.

The Parts of a Cut Diamond

After the diamond has been cut, shaped, and polished, it has a set of distinct and recognizable parts. The Gemological Institute of America lists and describes definitions for each of the parts of a cut diamond.

Nine listed definitions describe the proportions of each diamond, and these are:

  1. Table size 
  2. Total depth
  3. Pavilion depth
  4. Pavilion angle
  5. Crown height
  6. Crown angle
  7. Girdle thickness
  8. Lower girdle, and
  9. Culet.

Diamond Cut Diagram

The table is the flat top surface of the stone. The girdle is the widest edge of the diamond, while the pavilion refers to the lower part of the stone under the girdle. Finally, the culet is the bottom point of the gem.

As you may appreciate, a cut diamond’s proportions, along with the gems’ clarity, color, and size, vary enormously among the millions of jewelry quality stones on the market. As such, diamond grading and certifying processes are essential in setting the value of individual stones, and you should check such documents before you buy.

Why You Should Understand the Anatomy of a Diamond Before Buying

So, you ask, why do I need to know all this information about diamonds before I head to a jewelry store or buy a stone online? Because, armed with this new knowledge, you can understand how the different processes create the gemstone and how the parts of a cut diamond are crafted. The quality of the cut is the premier decider in setting the value of a diamond and knowing the type of faceting you’re after is a critical point in the buying decision.

Whether you’re buying an engagement ring, wedding bands, or other diamond jewelry, you want value for money. A quality stone with few blemishes and a cut that realizes the fire and brilliance effect you want is the aim. You should be able to negotiate with a jeweler for the best stone to suit your budget and purpose and walk away confident that you’ve made a great deal. Asking the right questions, comparing stones directly, and checking grading and certification documents will help enormously.

Deciding on the Best Diamonds for Your Settings

At Carbon Diamonds, we have an extensive range of lab-grown diamonds to fit every occasion and every type of setting. If you’re having trouble deciding upon the best diamond shape and cut, we will happily share our expert advice with you. In addition, we can craft a Bespoke piece to bring your idea to life if you’re after a unique design.

Contact us today for an exclusive private appointment at our showroom or schedule a virtual meeting.