Diamond Education

Almost everything written about diamonds is written by someone with a stake in what you conclude. This is our attempt at the opposite: the whole subject explained plainly, with the parts that cost you money separated from the parts that only sound like they do.

Start anywhere. If you are early, read this page top to bottom and you will know more than most people who walk into a jeweler. If you already know what you are looking for, the library at the bottom goes deeper on every individual topic.

The Four Grades, in the Order That Actually Matters

Every diamond is described by four attributes — cut, color, clarity and carat. They are almost always presented as equals. They are not.

Cut comes first, and it is not close. Cut is not the shape. It is how precisely the stone was faceted: the angles, the symmetry, and how effectively it sends light back to your eye. A well-cut stone looks alive. A poorly cut stone of identical weight, color and clarity looks flat and glassy. Cut is the only grade you should refuse to compromise, because it changes what the ring looks like every single day.

Carat is weight, not size. Two stones of identical weight can face up quite differently depending on shape and proportions. Elongated shapes cover more finger per carat than a round of the same weight.

Color and clarity are where money gets wasted. Both are graded under magnification, and both stop being visible long before they stop being expensive. The whole argument, with real numbers, is in the complete buying guide and the 4Cs explained.

How a Diamond Handles Light

"Sparkle" is not one thing. It is three separate optical effects, and once you can name them, every stone becomes easier to judge — and most marketing language becomes easier to see through.

Brilliance

The white light returned to your eye. Overall brightness. This is what makes a diamond read as bright across a room, and it is mostly a function of how much light enters the stone and comes back out of the top rather than escaping elsewhere.

Fire

That returned light split into flashes of spectral color — the reds, blues and oranges you catch as the stone moves. The proper term is dispersion. Fire is a function of facet angles and is most visible under point sources of light: candles, spotlights, sunlight.

Scintillation

The on-off sparkle pattern you see as the stone, the light source, or your own head moves. It is the contrast between facets flashing bright and going dark. Scintillation is what most people actually mean when they say a diamond "sparkles", and it comes from facet arrangement rather than from size or clarity.

What ruins all three

Poor proportions. If a stone is cut too deep or too shallow, light entering the top passes out through the bottom instead of returning to your eye. That is light leakage, and it is why a badly proportioned diamond can look glassy, or dark and empty through the center, no matter how good its grades read on paper. No clarity grade rescues a stone that leaks light.

Elongated shapes carry a specific version of this: the bow-tie effect, a dark band across the waist of an oval, pear or marquise where the facets shadow your own reflection back at you. Every elongated stone has one to some degree. Whether it is faint or disfiguring is visible only by looking, and no grading report records it.

This is the practical reason we insist on seeing stones before you do. A certificate describes a diamond. It does not show you one.

The trade colored stones make

One honest caveat, because it surprises people. A fancy color diamond is cut to maximize color saturation, not brilliance. Cutters use deeper pavilions so light travels further through the colored material, which strengthens the hue and costs some brightness and fire in return. Expect a vivid colored stone to return less white light than a well-cut colorless one. That is a deliberate bargain, not a defect — and anyone promising a vivid colored diamond that sparkles like a D-flawless round is describing a stone that does not exist.

Shape Is a Separate Decision from Cut

Shape is the outline — round, oval, cushion, emerald, pear, princess, radiant, marquise. Cut is the quality of the faceting within it. People use the words interchangeably; jewelers do not.

Shape is almost entirely personal, with two practical consequences worth knowing: elongated shapes face up larger per carat, and step cuts like emerald and Asscher show inclusions far more than brilliant cuts do, so they need better clarity. Every shape is compared properly in the diamond cuts and shapes guide.

Clarity: The Most Over-Purchased Grade

Clarity measures inclusions, assessed at 10x magnification. The threshold that matters is not a letter on the scale — it is eye-clean, meaning no inclusion is visible to normal vision at normal distance.

Most VS2 stones are eye-clean. Many SI1 stones are, depending on where the inclusion sits. Everything above VS1 is eye-clean by definition and equally so, because nothing is more invisible than invisible. Paying past that threshold buys a better line on a document.

Full detail in the clarity guide, and the specific question of whether the top grades are worth it in the VVS guide, which puts real prices against it.

Lab-Grown and Natural

Both are real diamonds. Same material, same hardness, same optical behavior. The difference is origin: one formed underground over a very long time, the other in a controlled environment over weeks. A gemologist cannot separate them with a loupe; specialist laboratory equipment identifies the growth process, not any difference in the stone.

Lab-grown runs typically 60–80% below a comparable natural stone, depending on size and grade. That gap is the single largest variable in any budget — larger than shape, setting, metal, or any grade decision on this page. We source both, so we have no reason to push you either way. The honest comparison is in lab-grown versus natural diamonds.

Certification: What the Report Does and Does Not Tell You

Never commit to a significant stone without an independent grading report.

For natural stones the reference standard is GIA. For lab-grown stones it is IGI, which built the grading protocols for them and remains the benchmark — our entire held catalog carries IGI reports. Both are credible; what matters is that a report exists and describes the stone in front of you.

What a report gives you is comparability: a specification you can hold against other stones and against the market. What it cannot give you is appearance. It does not record how evenly color is distributed, whether an oval has a disfiguring bow-tie, or how the stone behaves in ordinary room light rather than under a lamp chosen to flatter it. Those are the things somebody has to look at.

Fancy Color Diamonds

Once a stone's color is stronger than Z on the ordinary scale, it leaves that scale entirely and is graded under a separate system where color is the asset rather than the flaw. It is a genuinely different market with different rules, and we have built it out in depth:

• The fancy colored diamond guide — how color is graded and what actually drives the price.
• The GIA color intensity scale — Faint through Fancy Deep, and the two report fields that matter more than the grade.
• Natural pink diamonds — the Argyle closure, and what pink actually costs.
• Green diamonds — the hardest color to buy, and why the report is the purchase.
• Lab-grown fancy colors — what roughly $10,000 buys, hue by hue.
• Colored diamonds as an investment — the honest version.

What Any of This Costs

We publish real prices from our own catalog rather than ranges, including a carat ladder, what a grade upgrade actually costs on an otherwise identical stone, and the parts of a ring price that have nothing to do with the ring. It is all in what an engagement ring actually costs.

How We Use All of This

Reading this page will not make you a gemologist, and it does not need to. What it should do is let you ask better questions and recognize a straight answer when you hear one.

When you commission a piece with us, Dave sources candidates against your brief, reads the reports with you, examines the stones face-up before any reach you, and tells you plainly where each one compromises. Then he delivers the finished piece by hand. The whole process is set out on the concierge engagement ring page.

The Full Library

Common Questions