Things you need to know before purchase

💎 MadisonDia Premium Lab-Grown Diamond Standards ▼

Only International Gemological Institute (IGI) certified diamonds — ID EX / EX grade, each meeting our proprietary MISI™ (MadisonDia Ideal Sparkle Index) score of 80+.

MISI™ goes beyond the traditional 4Cs by evaluating advanced light performance — brilliance, fire, and scintillation — ensuring exceptional real-world sparkle, not just laboratory grading.

  • ✉️ After purchase, we'll email the IGI certificate for your review.
  • 💎 Not loving the diamond? Just say so — we'll show you 5+ replacements of the same size.
  • 🔄 Still not satisfied? Get a full refund, no fees — guaranteed.
📦 Shipping & Return ▼

Free Shipping on all purchases

💎 Loose Diamonds

  • Processing: 1–2 business days
  • Shipping: 3–8 business days (insured courier)
  • 30-day unconditional refund

💍 Finished Jewelry

  • Production: 5–15 business days
  • Shipping: 3–8 business days after production
  • Diamond portion refunded in store credits
  • Jewelry: USD $40 polishing & restock fee
  • 14-day refund window

Shipping details → Return & refund policy →

🏛️ Why Buy from Madison Avenue HK | MadisonDia ▼

A trusted name since 2012 — Madison Avenue is a well-known physical luxury boutique in Hong Kong. With a long and reliable track record, you can also verify our 5-star rating on BUYMA.

🔧 Free Repair Service

  • • Complimentary repair within the first year. After one year, repair costs are quoted separately.
  • • For side stones (if any, excluding the main diamond), one complimentary repair within the first year. Afterward, costs are quoted separately.
  • • Due to variations in craftsmanship, certain items may not be eligible for complimentary service. Excludes damage caused by human factors.