For Hina’s engagement rings, you can choose natural diamonds with the brand logo and certificate number laser-engraved on the girdle.

Only natural diamonds meeting the following quality standards are used:
• Carat (Weight): 7 sizes (0.20 ct～, 0.23 ct～, 0.25 ct～, 0.28 ct～, 0.30 ct～, 0.33 ct～0.35 ct, 0.50 ct～0.52 ct)
• Color: 4 grades (D, E, F, G)
• Clarity: 5 grades (IF, VVS1, VVS2, VS1, VS2)
• Cut: All 3EX (Triple Excellent / Heart & Cupid)

Certificates are issued by:
• CGL (Central Gem Laboratory)
• DGL (Diamond Grading Laboratory)
• GIA-Japan (AGT Gem Laboratory)

By verifying the certificate and girdle number, you can immediately identify the same diamond. Note that the diamonds in the Kohina, Komomo, Kobeni, and Junin-to-Iro series do not have girdle inscriptions.

Additionally, only non-conflict diamonds that do not fund terrorism are used.