IGI-Certified Diamonds
Choose your desired lab-grown diamond with complete confidence.

| US | UK / Australian Size | Inside Diameter (mm) | Circumference (mm) |
|---|---|---|---|
| 3 | F | 14.1 | 44.2 |
| 3.5 | G | 14.5 | 45.5 |
| 4 | H½ | 14.9 | 46.8 |
| 4.5 | I½ | 15.3 | 48.0 |
| 5 | J½ | 15.7 | 49.3 |
| 5.5 | K½ | 16.1 | 50.6 |
| 6 | L½ | 16.5 | 51.9 |
| 6.5 | M½ | 16.9 | 53.1 |
| 7 | N½ | 17.3 | 54.4 |
| 7.5 | O½ | 17.7 | 55.7 |
| 8 | P½ | 18.1 | 57.0 |
| 8.5 | Q½ | 18.5 | 58.3 |
| 9 | R½ | 19.0 | 59.5 |
| 9.5 | S½ | 19.4 | 60.8 |
| 10 | T½ | 19.8 | 62.1 |
| 10.5 | U½ | 20.2 | 63.4 |
| 11 | V½ | 20.6 | 64.6 |
| 11.5 | W½ | 21.0 | 65.9 |
| 12 | X½ | 21.4 | 67.2 |
| 12.5 | Z | 21.8 | 68.5 |
| 13 | Z+1 | 22.2 | 69.7 |
| KA Size | Wrist Diameter (in) | Wrist Diameter (cm) |
|---|---|---|
| Extra Small | 4.76 – 5.25 | 12.1 – 13.3 |
| Small | 5.26 – 5.75 | 13.4 – 14.6 |
| Medium | 5.76 – 6.25 | 14.6 – 15.9 |
| Large | 6.26 – 6.75 | 15.9 – 17.1 |
| Extra Large | 6.76 – 7.25 | 17.2 – 18.4 |
| Extra Extra Large | 7.26 – 7.75 | 18.4 – 19.7 |
| Extra Extra Extra Large | 7.76 – 8.25 | 19.7 – 21.0 |
| Length (in) | Length (cm) |
|---|---|
| 16 | 40.50 |
| 18 | 45.75 |
| 20 | 50.75 |
| 24 | 61.00 |
| 30 | 76.25 |
| 36 | 91.50 |
Choose your desired lab-grown diamond with complete confidence.
Review and approve your design before production begins.
Customize your diamond, metal, engraving.
Covered by our lifetime manufacturing warranty.
Created with lab-grown diamonds and recycled precious metals.
Add a meaningful complimentary engraving.
Every lab-grown diamond at The Altered Carbon comes with an official IGI certification, ensuring complete authenticity and quality assurance. Each diamond is independently graded by the International Gemological Institute (IGI) based on its cut, color, clarity, and carat weight—giving you full transparency in your purchase.
Our IGI certified lab-grown diamonds are ethically created and precisely evaluated to meet global standards, making them a trusted choice for modern fine jewelry. This certification not only guarantees the quality of your diamond but also adds long-term value and credibility to your investment.
Whether you are choosing an engagement ring or a timeless piece, you can shop with confidence knowing your diamond is verified, certified, and crafted to perfection.