The radiant is the shape that refused to choose. Its outline is step-cut architecture — a rectangle with the four corners cropped, the same silhouette as an emerald cut — while the faceting inside is brilliant, so it throws fire where a step cut would hold still. IGI grades this 1.00 carat lab grown diamond under its formal description, cut cornered rectangular modified brilliant; the trade has called that combination a radiant since the 1970s. Report LG653445126 records D color, VS 1 clarity, excellent polish and excellent symmetry, and the stone sits unset among our loose lab grown diamonds.
1.00 Carat
D Color
VS 1 Clarity
Cut Cornered Rectangular Brilliant
IGI Certified
Excellent Polish & Symmetry
Emerald-cut architecture, brilliant-cut fire
The IGI report does not use the word radiant anywhere. It states the shape and cutting style as cut cornered rectangular modified brilliant, which is the formal, descriptive way of saying the same thing: corners cropped rather than pointed, an outline longer than it is wide, and faceting from the brilliant family rather than the step family. The trade name for exactly that combination is radiant, and both descriptions are accurate.
The hybrid is the whole appeal. A true step cut — emerald, Asscher — uses long parallel facets that behave like a hall of mirrors: broad, architectural, quiet, and unforgiving of anything trapped inside the stone. The radiant keeps that clean cropped-corner outline and replaces the interior with brilliant faceting, so you get the tailored silhouette of an emerald cut with scintillation much closer to a round. Finished pieces in the radiant cut engagement rings collection show how differently the two read side by side.
This one measures 6.99 x 4.94 x 3.31 mm, a length-to-width ratio of 1.41:1. That is genuinely elongated — enough to lengthen a finger and to make the stone look larger than a square outline of the same weight — without the drama of a marquise or a pear. The depth of 3.31 mm is about 67 percent of the 4.94 mm width, which is where the brilliant faceting does its work.
What D, VS 1 and the finish grades tell you
D is the top of the color scale, the colorless end, with nothing graded above it. A radiant’s brilliant faceting is more forgiving of body color than a step cut is, because scattered light disguises a tint that a broad open table would show plainly. Choosing D on a radiant is therefore a generous decision rather than a necessary one, and fluorescence is graded None, so the stone holds the same appearance under any light.
VS 1 means very slightly included: the characteristics are difficult for a grader to find at 10x magnification and invisible to the unaided eye. The same faceting that hides color also hides inclusions, which is one reason radiants are often better value at a given clarity than an emerald cut, where every internal feature is on show through the table.
Polish and symmetry are both graded Excellent. No overall cut grade is stated, and none should be: cut grades are issued for round brilliants, so a fancy shape report gives you the finish grades and the measurements instead. Our complete guide to lab grown diamonds and the 4Cs guide both go through what each line on a report is actually telling you.
Settings a radiant is built for
Cropped corners are a gift to a setter. There are no points to shield and no ninety-degree angles to chip, so a plain four-prong head sits on the corners naturally and needs no special engineering — which is why radiants look so composed in minimal, modern settings.
The elongated outline also suits an east-west orientation, laid across the finger rather than along it, and a hidden halo suits it particularly well: a ring of small stones tucked under the girdle lifts the apparent size without adding anything to the clean rectangle you see from above. Three-stone designs with trapezoid or baguette sides echo the cropped corners. Look at hidden halo engagement rings and the lab grown diamond engagement rings for worked examples, or read the survey of ring styles and setting types first.
How it was grown, and what Type IIa means
IGI’s comments read: created by Chemical Vapor Deposition (CVD) growth process, Type IIa. In CVD growth a thin diamond seed sits in a sealed chamber of carbon-rich gas, energy breaks the gas apart, and carbon settles onto the seed atom by atom until a single crystal has built up over several weeks. How lab grown diamonds are made covers the equipment and the timescale.
Type IIa is a chemical classification, not a quality grade. It means the crystal is essentially free of nitrogen, the impurity that gives many diamonds a faint yellow cast. Type IIa material makes up a very small fraction of mined diamond and is common in CVD growth, which is part of why colorless grades are easier to reach this way.
There is no mine behind the stone, so it is conflict-free by origin. If you are still weighing the decision on price and value rather than sourcing, are lab grown diamonds worth it answers it without overselling the case.
Every line below is transcribed from IGI report LG653445126, with the ratio and depth percentage calculated from the measurements it states. Diamond is April’s birthstone, which gives a certified loose stone a second occasion — see April birthstone jewelry.
-
Stone Laboratory grown diamond
-
Shape and cut Cut cornered rectangular modified brilliant (the trade name is radiant)
-
Carat weight 1.00 carat
-
Measurements 6.99 x 4.94 x 3.31 mm
-
Length to width 1.41:1 (calculated from the measurements)
-
Depth 3.31 mm, about 67% of the 4.94 mm width
-
Color grade D
-
Clarity grade VS 1
-
Cut grade Not stated on this report
-
Polish Excellent
-
Symmetry Excellent
-
Fluorescence None
-
Growth method Chemical Vapor Deposition (CVD)
-
Diamond type Type IIa
-
Inscription IGI LG653445126, laser-inscribed on the girdle
-
Report IGI LG653445126, issued September 25, 2024
-
Birthstone April
-
Custom setting Available
Certification & care
The stone ships with IGI report LG653445126, issued September 25, 2024, and the same number is laser-inscribed on its girdle. Enter it into IGI’s online report check and the grading record comes back independently of anything written here, which is the practical value of a certified stone: you are not buying a description, you are buying a document you can audit. IGI vs GIA certification explains how the two major laboratories differ.
The dimensions to design around are 6.99 x 4.94 x 3.31 mm. Give them to whoever makes the setting before the head is fabricated, because a 1.41:1 rectangle needs a head cut to those proportions — a generic square or oval seat will not hold it correctly.
At Mohs 10 the diamond itself is effectively unscratchable in normal use, but a loose stone is easy to misplace and easy to let go dull. Keep it in the box it arrives in, away from softer stones it would damage. Warm water, mild dish soap and a soft brush clears the skin oil off the pavilion that flattens a radiant’s fire faster than anything else; dry it on a lint-free cloth. Our notes on cleaning jewelry at home carry over once the stone is set.
Radiant lab grown diamond questions
Why does the IGI report not use the word radiant?
Because IGI describes shapes by their construction rather than by trade names. The report reads cut cornered rectangular modified brilliant, which describes precisely what the stone is: cropped corners, a rectangular outline, brilliant-family faceting. Radiant is the name the trade gave that combination, and it refers to the same cut. Both terms are correct; only one of them appears on the certificate.
Is a lab grown diamond a real diamond?
Yes. This is diamond in every measurable sense — the same carbon crystal, Mohs 10 hardness, the same refractive index — and IGI grades it on the identical scales used for any other diamond. Where the crystal formed is the only difference. Our article on whether lab grown diamonds are real diamonds covers it, and moissanite vs lab grown diamond is the comparison to read if that is the other stone on your list.
Radiant or emerald cut: which should I choose?
They share an outline and behave nothing alike. An emerald cut is a step cut: long parallel facets, broad flashes, a calm architectural look, and every inclusion visible through the open table. A radiant keeps the cropped-corner rectangle but fills it with brilliant faceting, so it sparkles far more, hides inclusions and color better, and reads as livelier than tailored. Choose on which of those two behaviors you want to look at every day.
What does Type IIa mean?
It is a chemical classification, not a quality grade. Type IIa diamonds are essentially free of nitrogen, the impurity responsible for a faint yellow cast in many diamonds. It is rare in mined material and common in CVD growth, and it is one reason colorless grades like this D are achievable. It says nothing on its own about cut, clarity or beauty.
How white is D color?
D is the very top of the scale, with no grade above it and no detectable body color. On a radiant it is arguably more color than you need, because brilliant faceting scatters light in a way that masks a faint tint. If budget were the constraint, a lower color grade would still look colorless in this shape; D removes the question entirely.
Is VS 1 eye-clean in a radiant?
Yes. VS 1 means very slightly included, a grade at which a trained grader has to search for the characteristics at 10x magnification. The radiant’s faceting scatters light across many small facets, which conceals internal features far more effectively than an emerald cut’s open table, so VS 1 in this shape is comfortably beyond what an eye can resolve.
Why is there no cut grade on the report?
Overall cut grades are issued for round brilliants. Fancy shapes are not graded that way, so the report states polish and symmetry, both Excellent here, and publishes the measurements so you can assess the proportions yourself. We will not print a cut grade that IGI did not assign.
What does a 1.41:1 ratio look like on the hand?
Clearly rectangular but not stretched. The stone measures 6.99 mm long by 4.94 mm wide, so it is about 40 percent longer than it is broad. That is enough elongation to lengthen the look of a finger and to give the stone more presence than a square outline of the same weight, while staying well short of the exaggerated proportions of a marquise. Ratios near 1.30 to 1.50 are the range most people find balanced in a radiant.
What is laser-inscribed on the stone, and how do I check the report?
The girdle carries IGI LG653445126, matching the report number. It needs magnification to read and is invisible in wear. To check the report, enter that number on IGI’s online report-check page; the grading record it returns should match every figure quoted on this listing.
Can this diamond be set into a ring, and who does that work?
Yes. Aquamarise builds custom rings around loose stones, so this radiant can be set into whatever design you choose, with the setting and the final band sizing carried out together at the bench — both are a jeweler’s job and neither is something you need to arrange yourself. Start at build your custom ring and quote the report number so the head is made to these exact dimensions.
Will it test as a diamond, and can it be appraised?
It tests as diamond on a standard thermal tester because it is diamond. For insurance you will want a written valuation rather than a tester reading, and the IGI report plus the girdle inscription give an appraiser everything they need to identify and value the stone. Our appraisal page explains how we handle that.
How do I clean and store a loose diamond?
Warm water, a drop of mild dish soap, a soft brush and a lint-free cloth. Skin oil on the pavilion is what kills a radiant’s fire, and it lifts off in under a minute. Store the stone in its own box: at Mohs 10 it will scratch anything softer that it shares a drawer with.
How does it ship, and what is the return policy?
Loose stones ship free within the USA, insured and tracked, with the IGI report in the parcel. The terms that apply to returning a loose stone are set out in full on our returns and refunds page; read them before ordering, especially if you intend to have the diamond set.
