A report grade is the starting point
A laboratory report tells you a diamond meets a recognised grading standard. SAAT Select Cut is a further, narrower screen we run on the certificate data of every diamond we list — before it ever reaches your search results. A diamond can pass its laboratory grading and still fall outside SAAT Select Cut if its proportions sit outside our published ranges.
SAAT Select Cut is our own retail screening standard. It supplements the independent laboratory report; it does not replace or alter the laboratory's grade, and it should not be confused with a laboratory cut grade itself.
What GIA Triple Excellent means
For a GIA-graded round brilliant, Triple Excellent commonly means three separate Excellent results: overall cut grade, polish, and symmetry. It's a respected quality baseline — but it doesn't mean every Triple Excellent diamond has the same proportions or the same face-up personality. GIA's system permits multiple proportion combinations within "Excellent," and the final cut grade also considers finish, girdle, culet, and other factors GIA doesn't publish stone by stone.
How SAAT Select Cut is different
| Question | GIA Triple Excellent | SAAT Select Cut |
|---|---|---|
| Who assigns it | GIA assigns the laboratory grade on an eligible round brilliant report. | SAAT screens the exact stone's certificate data against our own published ranges. |
| What it covers | Excellent cut, polish, and symmetry for a standard round brilliant. | Tighter round screening plus shape-specific screening for fancy shapes. |
| Proportion range | Allows multiple proportion combinations that can receive Excellent. | Uses narrower target ranges designed to reduce weak combinations. |
| Fancy shapes | The GIA Triple Excellent label is not an overall fancy-shape cut grade — GIA doesn't assign one. | SAAT publishes length-to-width ratio, depth, and table screening ranges for each fancy shape. |
| Final result | The report communicates GIA's independent assessment. | A stone can pass its GIA report and still fall outside SAAT Select Cut on proportions. |
SAAT Select Cut screening ranges
These ranges are selection filters, not stand-alone promises of beauty. They're designed for modern colourless and near-colourless brilliant or step-cut centre diamonds. Antique cuts, custom facet designs, fancy-colour diamonds, and distinctive artistic cuts fall outside this screen. "Preferred" length-to-width ratios express a balanced, commercially popular appearance — not a rule against personal preference for a wider or narrower stone.
| Shape | L/W ratio | Depth | Table |
|---|---|---|---|
| Round brilliant | 1.00–1.02 | 60.0–62.3% | 54–58% |
| Oval brilliant | 1.35–1.50 | 60–63% | 55–61% |
| Pear brilliant | 1.45–1.75 | 58–63% | 55–62% |
| Marquise brilliant | 1.75–2.15 | 58–63% | 55–62% |
| Emerald cut | 1.30–1.50 | 60–68% | 58–67% |
| Asscher cut | 1.00–1.05 | 60–68% | 58–67% |
| Radiant cut | 1.00–1.40 | 61–69% | 58–68% |
| Cushion brilliant | 1.00–1.30 | 61–68% | 55–65% |
| Princess cut | 1.00–1.05 | 64–75% | 62–72% |
| Heart brilliant | 0.90–1.10 | 57–63% | 55–62% |
Every shape also requires polish and symmetry of at least Very Good, a girdle between Thin and Slightly Thick (faceted), and a culet of None to Very Small. Round brilliants are held to the tightest bar of all: GIA Excellent overall cut grade, Excellent polish and symmetry, a crown angle of 34.0–35.0°, and a pavilion angle of 40.6–40.9° — angles GIA doesn't publish a target range for on the report itself, but which strongly affect brightness and light return.
What SAAT Select Cut checks — and what it doesn't
SAAT Select Cut is a proportion and craftsmanship screen, run automatically against every diamond's certificate data. It checks the measurements above, plus finish (polish, symmetry), girdle, and culet. It does not include a stone-by-stone optical review of light performance, bow-tie, windowing, or transparency — those visual characteristics vary by individual stone and lighting condition, and we encourage you to view a diamond's photos and video, and ask us directly, before deciding on a fancy-shape stone where bow-tie or windowing can vary meaningfully even within our screening ranges.
Frequently asked questions
Is SAAT Select Cut a laboratory cut grade? No. It's SAAT's own disclosed screening standard, run against the independent laboratory report's data. The laboratory report remains separate and can be verified with the issuing laboratory.
Is every GIA Triple Excellent round a SAAT Select Cut diamond? No. Triple Excellent is the entry requirement for a GIA round, but SAAT applies narrower target proportions, including angle targets GIA doesn't publish a range for.
Does a preferred ratio mean other ratios are unattractive? No. Ratio is partly aesthetic. SAAT publishes a balanced default range for each shape; if you prefer a longer or shorter stone outside that range, our team can help you find one — it just won't carry the SAAT Select Cut label.
Does SAAT Select Cut guarantee maximum sparkle in every light? No diamond looks identical in every environment. The screen targets proportions associated with strong, repeatable light performance — it isn't an absolute claim about how any individual stone will look in every setting.
Does fluorescence decide cut quality? No. Fluorescence is a separate characteristic from the proportions SAAT Select Cut screens.
An important note on proportions
Proportion ranges are useful screening filters, but they don't calculate beauty by themselves. Measurements are rounded, facets interact, and appearance depends on the stone's full three-dimensional structure. This standard is SAAT's own purchasing and selection policy — it is not an independent laboratory opinion, a valuation, or a guarantee of future value.