Buy a 1-carat round diamond – Price & Size

1-carat round diamonds

A 1-carat round diamond measures approximately 6.5 mm in diameter, making it the size most people use as a benchmark. As a compromise, grades G through H for color and VS2 through SI1 for clarity are a good choice, because the round cut effectively conceals small inclusions. Lab-grown diamonds are significantly less expensive than comparable natural diamonds.

Stone	Form			Purity		Pol.	Sym.	Fluorine.	Laboratory	Dimensions	L/W	Table	Depth	Delivery Time
360°	Round	1,04	D	VVS1	Excellent	EX	EX	None	IGI	6.46 × 6.49 × 4.01	1,00	58 %	61,9 %	7–9 wt.	940 €
360°	Round	1,04	D	VVS1	Ideal	EX	EX	None	IGI	6.45 × 6.48 × 3.99	1,00	59 %	61,6 %	7–9 wt.	940 €
360°	Round	1,26	E	VVS2	Excellent	EX	EX	None	IGI	6.91 × 6.94 × 4.21	1,00	60 %	60,8 %	7–9 wt.	1.060 €
360°	Round	1,04	D	VVS1	Ideal	EX	EX	None	IGI	6.52 × 6.56 × 3.99	0,99	58 %	61,0 %	7–9 wt.	940 €
360°	Round	1,04	D	VVS1	Excellent	EX	EX	None	IGI	6.41 × 6.45 × 4.05	0,99	57 %	63,0 %	7–9 wt.	940 €
360°	Round	1,04	D	VVS1	Ideal	EX	EX	None	IGI	6.44 × 6.47 × 4.03	1,00	58 %	62,4 %	7–9 wt.	940 €
360°	Round	1,28	E	VVS2	Excellent	EX	EX	None	IGI	6.96 × 7.00 × 4.26	0,99	59 %	60,9 %	7–9 wt.	1.080 €
360°	Round	1,04	D	VVS1	Excellent	EX	EX	None	IGI	6.53 × 6.55 × 3.95	1,00	59 %	60,5 %	7–9 wt.	940 €
360°	Round	1,04	D	VVS1	Ideal	EX	EX	None	IGI	6.47 × 6.49 × 4.04	1,00	58 %	62,2 %	7–9 wt.	940 €
360°	Round	1,05	D	VVS1	Excellent	EX	EX	None	IGI	6.43 × 6.46 × 4.04	1,00	58 %	62,6 %	7–9 wt.	950 €
360°	Round	1,06	E	VVS2	Ideal	EX	EX	None	IGI	6.51 × 6.54 × 4.03	1,00	60 %	61,8 %	7–9 wt.	910 €
360°	Round	1,23	D	VVS2	Excellent	EX	EX	None	IGI	6.79 × 6.82 × 4.28	1,00	60 %	62,8 %	7–9 wt.	1.040 €
360°	Round	1,26	D	VVS2	Ideal	EX	EX	None	IGI	6.92 × 6.95 × 4.30	1,00	56 %	62,0 %	7–9 wt.	1.060 €
360°	Round	1,28	D	VVS2	Ideal	EX	EX	None	IGI	6.96 × 7.00 × 4.27	0,99	59 %	61,2 %	7–9 wt.	1.080 €
360°	Round	1,03	E	VS1	Ideal	EX	EX	None	IGI	6.43 × 6.46 × 4.03	1,00	58 %	62,5 %	7–9 wt.	830 €
360°	Round	1,00	E	VS1	Ideal	EX	EX	None	IGI	6.37 × 6.45 × 3.95	0,99	56 %	61,5 %	7–9 wt.	810 €
360°	Round	1,05	E	VS1	Ideal	EX	EX	None	IGI	6.49 × 6.52 × 4.05	1,00	57 %	62,2 %	7–9 wt.	840 €
360°	Round	1,02	E	VS1	Ideal	EX	EX	None	IGI	6.40 × 6.43 × 3.99	1,00	58 %	62,2 %	7–9 wt.	820 €
360°	Round	1,04	E	VVS1	Ideal	EX	EX	None	IGI	6.44 × 6.49 × 3.99	0,99	59 %	61,6 %	8–10 wt.	910 €
360°	Round	1,04	E	VVS1	Ideal	EX	EX	None	IGI	6.45 × 6.51 × 4.00	0,99	59 %	61,8 %	8–10 wt.	910 €
360°	Round	1,04	E	VVS1	Ideal	EX	EX	None	IGI	6.51 × 6.54 × 4.00	1,00	57 %	61,3 %	8–10 wt.	910 €
360°	Round	1,04	E	VVS1	Ideal	EX	EX	None	IGI	6.51 × 6.54 × 3.99	1,00	59 %	61,1 %	8–10 wt.	910 €
360°	Round	1,05	E	VVS1	Ideal	EX	EX	None	IGI	6.50 × 6.54 × 4.04	0,99	57 %	61,9 %	8–10 wt.	920 €
	Round	1,03	D	VS1	Ideal	EX	EX	None	IGI	6.49 × 6.52 × 4.00	1,00	57 %	61,4 %	4–6 wt.	950 €

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.5 mm

940 €IGI

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.5 mm

940 €IGI

360°

1.26 ct · Round

Colour E · VVS2

Ø 6.9 mm

1,060 €IGI

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.5 mm

940 €IGI

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.4 mm

940 €IGI

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.5 mm

940 €IGI

360°

1.28 ct · Round

Colour E · VVS2

Ø 7.0 mm

1,080 €IGI

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.5 mm

940 €IGI

360°

1.04 ct · Round

Colour D · VVS1

Ø 6.5 mm

940 €IGI

360°

1.05 ct · Round

Colour D · VVS1

Ø 6.4 mm

950 €IGI

360°

1.06 ct · Round

Colour E · VVS2

Ø 6.5 mm

910 €IGI

360°

1.23 ct · Round

Colour D · VVS2

Ø 6.8 mm

1,040 €IGI

360°

1.26 ct · Round

Colour D · VVS2

Ø 6.9 mm

1,060 €IGI

360°

1.28 ct · Round

Colour D · VVS2

Ø 7.0 mm

1,080 €IGI

360°

1.03 ct · Round

Colour E · VS1

Ø 6.4 mm

830 €IGI

360°

1.00 ct · Round

Colour E · VS1

Ø 6.4 mm

810 €IGI

360°

1.05 ct · Round

Colour E · VS1

Ø 6.5 mm

840 €IGI

360°

1.02 ct · Round

Colour E · VS1

Ø 6.4 mm

820 €IGI

360°

1.04 ct · Round

Colour E · VVS1

Ø 6.5 mm

910 €IGI

360°

1.04 ct · Round

Colour E · VVS1

Ø 6.5 mm

910 €IGI

360°

1.04 ct · Round

Colour E · VVS1

Ø 6.5 mm

910 €IGI

360°

1.04 ct · Round

Colour E · VVS1

Ø 6.5 mm

910 €IGI

360°

1.05 ct · Round

Colour E · VVS1

Ø 6.5 mm

920 €IGI

1.03 ct · Round

Colour D · VS1

Ø 6.5 mm

950 €IGI

All prices include 19% VAT · 14-day right of withdrawal · Stones are sold individually and may be sold out on short notice.

Carat	Approx. size (mm)
0.5 ct	approx. 5.1 mm
1 ct	approx. 6.5 mm
1.5 ct	approx. 7.4 mm
2 ct	approx. 8.1 mm
3 ct	approx. 9.3 mm

Carat

Approx. size (mm)

0.5 ct

approx. 5.1 mm

1 ct

approx. 6.5 mm

1.5 ct

approx. 7.4 mm

2 ct

approx. 8.1 mm

3 ct

approx. 9.3 mm

What to Look for in Round Diamonds

Cut: Only here is there an overall grade

Round is the only shape for which the GIA and IGI assign a cut grade of “Excellent” or lower. This grade encompasses proportions, polish, and symmetry and is the single most important factor in a diamond’s brilliance. Look at this first, then at the rest. Two stones with the same carat weight, colour, and clarity can differ significantly based solely on their cut.

Colour and Purity: Where the Sweet Spot Lies

The round brilliant cut refracts light more strongly than any other cut, thereby concealing small inclusions. VS2 and, often, SI1 diamonds appear clear to the naked eye as long as the inclusions are not centreed beneath the table. As for colour, a grade of G to H is sufficient to create an impression that is virtually indistinguishable from colourless, especially in white gold or platinum.

Size: What One Carat Means in Millimeters

One carat equals 0.2 grams; it is therefore a unit of weight, not a unit of size. A round diamond weighing 1 ct measures approximately 6.5 mm in diameter, while a 2 ct diamond measures approximately 8.1 mm. Although the weight doubles, the visible diameter increases by only about a quarter. If you’re looking for visual size, you should also make sure the stone’s depth isn’t too great.

Frequently Asked Questions

How big is a 1-carat round diamond?

The diameter is approximately 6.5 mm; the exact measurement depends on the proportions. Two stones of identical weight may differ by one to two tenths of a millimeter, depending on how much mass is concentrated toward the center. Stones cut flatter appear larger when viewed from above.

What level of quality is worth it for a 1-carat diamond?

For a well-balanced result, G to H in color and VS2 to SI1 in clarity provide a good foundation, combined with a high cut grade. The cut has the greatest visible effect in a 1-carat diamond; cutting corners here is more noticeable than a lower color grade.

Lab-grown diamond or natural diamond?

Lab-grown diamonds and natural diamonds are both composed of pure carbon and share the same crystal structure, hardness, and refractive index. The difference lies in their formation: one forms over millions of years in the Earth’s crust, while the other is created in a matter of weeks in a laboratory. Visually, they are indistinguishable without specialized laboratory equipment. Lab-grown diamonds are significantly less expensive than comparable natural diamonds, which is why you can often get more carats or a higher clarity grade for the same budget. Both types are certified by IGI or GIA; you can look up the report number directly with the lab.