A diamond certificate is like a diamond’s ID card. Blue Nile and James Allen were once two of the world’s top online diamond retailers. Here is a new update: James Allen is now part of Blue Nile. Their diamond inventories have fully combined together. When it comes to diamond documents, the most well-known and reliable ones are from GIA, IGI and AGS. AGS have much stricter rules for diamond cut grading.
GIA Certificate (The Most Important One)
Both Blue Nile and James Allen highly recommend natural diamonds with GIA certificates, especially for stones over 0.5 carats. GIA is the most strict and trusted lab in the jewelry industry. The famous 4C standard for diamonds was created by GIA. Diamonds with GIA papers use unified grading rules. They are easy to compare, and also hold their value better over time.
My shopping advice: No matter where you buy diamonds, always pick those with GIA certificates first. It is the best way to aviod confusion and guarantee real quality.
What is AGS Certificate?
AGS stands for American Gem Society. It is an organization that protect consumers and share professional jewelry knowledge. AGS Laboratories issues official diamond grading reports, known as AGS certificates. This lab earn great fame for its advanced cut grading system. AGS is highly authoritative. Its cut evaluation is widely seen as one of the most precise in the trade. AGS enjoys the same good reputation as GIA, and both are top trusted diamond certificate providers.
IGI Certificate
Both retailers also carry diamonds with IGI certificates. IGI is extremly popular in the lab-grown diamond market, and its standards are widely accepted around the world.
Blue Nile keeps a large stock of natural diamonds with IGI certificates. Customers need to check the certificate type carefully when making choices.
All Blue Nile diamonds are worth buying? 1，Both milky tint and brown hue:Tap to see full diamond info 2，The diamond has milkiness:Click to view detailed diamond information 3，The diamond has medium green fluorescence.:View details 4，The diamond has a cavity:See details
In-house or Other Commercial Certificates
For tiny diamonds below 0.5 carats, or finished set jewelry, both brands may use their own in-house certificates or other commercial papers.
Important warning: You need to be very careful with these diamonds. In-house grading standard are not as strict as GIA or IGI. Grade inflation often happen here. For example, a diamond graded SI2 may be marked as VS. Ordinary buyers can hardly tell the real difference.
Shopping tip: Try your best to stay away from diamonds with only in-house certificates. Only choose them if you fully trust the brand or you have a very tight budget. Stick to GIA or IGI certificates to keep yourself safe.
Visual Technology (Great Helper for Online Shopping)
Both platforms own excellent online video tools. Blue Nile provides 360° high-definition videos for every single diamond. With the free real-time inspection function, you can zoom in, rotate and check every facet closely. You can clearly see the exact position of inclusions and how serious the bow-tie effect is. This experience is almost the same as viewing the diamond in person.
Final Reminder
Always stay alert. Do not buy diamonds that only come with seller’s own certificates, without GIA or IGI reports. New buyers should skip these items, unless the price is really attractive and you are willing to take the risks.