GIA New York and IGI: Where Diamond Grading Reports Come From

Two of the best-known diamond grading laboratories work in Midtown Manhattan. GIA's New York laboratory is at 50 W 47th Street, in the International Gem Tower in the Diamond District, and IGI's is at 545 Fifth Avenue. GIA lists D-to-Z diamond grading and a separate lab-grown diamond quality assessment; IGI lists certification services for natural and lab-grown diamonds. Both publish instructions for submitting stones directly.

Which diamond grading labs are in New York?

GIA on 47th Street

GIA lists its New York laboratory at 50 W 47th Street, Unit 400. GIA's locations listing, retrieved in September 2026, gave these hours: Monday to Thursday, 9 a.m. to 5:15 p.m., and Friday, 8:30 a.m. to 5 p.m. The lab's number is +1 212 221 5858. Hours can change, so confirm them on that page before you plan around them.

The building matters. According to GIA, its New York campus is in the International Gem Tower, in the middle of the Diamond District and a few feet from thousands of jewelry businesses. GIA also says the vast majority of diamonds entering the United States pass through New York, and that jewelry is New York's third largest industry. GIA moved its laboratory into the 80,000 square foot, three-floor facility in mid-March 2014. Its board formally inaugurated it that May. The space holds GIA's research, laboratory services and education under one roof, and gemology classes began there on May 27, 2014.

That is also the answer to a question people often search: yes, there is a GIA school in New York. The campus runs lab classes in diamond grading, colored stone grading, gem identification and pearl grading.

IGI on Fifth Avenue

IGI's New York office is at 545 Fifth Avenue, 11th floor, New York, NY 10017. It houses both a gemological lab and a School of Gemology. IGI notes that Midtown sits close to the Diamond District on 47th Street. Its school lists hands-on courses including Diamond Grading Essentials, Introduction to Jewelry Grading and Jewelry Quality Control.

IGI marked its move to 545 Fifth Avenue with a reception on March 16. According to IGI, the expanded offices cover two floors and over 20,000 square feet. The building dates from 1897, when it opened as a hotel, and was converted to offices in 1930.

If you want the wider picture of how the trade works around these two labs, our guide to buying diamonds in New York City covers it.

What does a grading report actually tell you?

A grading report is a laboratory's description of one stone. The information provided depends on the lab and the report type; check the issuing laboratory's explanation of the report you have.

• Identification. Check how the report identifies the diamond as natural or lab-grown.

It records the laboratory's findings about the stone, separate from a seller's description.

A report is not an appraisal. It does not say what a stone is worth, and it should not be read as a promise about what you could sell it for later. IGI offers appraisals as a separate service from its grading reports, which tells you the two are different documents. We don't value stones. Diamonds are not investments, and a good report doesn't change that.

Our glossary entry on certificates explains each line of a report in plain terms. Every diamond we sell comes with a GIA or IGI grading report.

How do natural and lab-grown diamond reports differ?

First, check how the report identifies the stone. Both labs treat natural and lab-grown diamonds as separate categories.

GIA's service list names D-to-Z diamond grading and a separate "Laboratory-Grown Diamond Quality Assessment". IGI's New York page lists certification services for natural diamonds and lab-grown diamonds as separate items. It also says IGI screens every diamond it receives to determine whether it was mined or grown. In IGI's own words, it screens "millions of natural and lab grown diamonds" so that the trade and consumers get what they expect.

GIA discussed its work on detecting grown and treated gems in a 2014 announcement. In 2014, its board increased funding for research into detecting synthetic and treated gems. According to GIA's 2014 announcement, its research team then had 38 full-time scientists, 20 of them with doctoral degrees.

For you as a buyer, the difference is simple. A lab-grown diamond is a diamond, grown rather than mined, and its report should identify it as lab-grown. Our glossary page on the lab-grown diamond explains how one is made and graded.

Can you send a stone to GIA or IGI yourself?

Both labs publish submission instructions. Check each lab's published instructions before submitting a stone. Here is how each describes the process. For anything specific to your stone or your shipment, ask the lab or your courier.

GIA's process

GIA says you can submit diamonds, colored stones and pearls directly to any of its laboratory locations. The main steps are:

• Open an account first. You must have a GIA laboratory service account before you submit anything.
• Paying by card. If you are not submitting in person, you call the laboratory you are shipping to and give your card details over the phone.
• Packing. Wrap each item in its own parcel paper.
• The memo. Include a memo with your account details, the service you want for each stone (with its size and shape), and your return instructions.
• Payment before return. Payment is due in full before reports and items come back, unless you are approved to invoice.

Services vary by location. If you send an item to a lab that doesn't offer the service you asked for, GIA moves it securely to the right laboratory and returns it to its point of origin, with additional shipping charges. GIA also notes that its New York location uses different shipping addresses depending on the shipping method, so check the addresses on the location page before you send anything.

If a stone is coming from abroad, GIA's instructions carry two dated notes:

• As of February 1, 2025, international shipments entering the U.S. may be subject to tariffs or import duties, and GIA says these are the sender's responsibility.
• GIA's shipping instructions describe a requirement it says was announced on March 1, 2024, for internationally shipped diamonds of 1.00 carat or more entering the U.S.: a signed, dated letter on company letterhead using specified language about Russian origin and production, including transformation outside Russia. Check GIA's current instructions and the relevant official customs guidance with your courier before shipping.

GIA says these rules are subject to change and points senders to their courier or customs broker.

IGI's process

IGI's submission guide describes two routes:

• In person at 545 5th Avenue, 11th Floor in New York.
• By mail to the same address. The guide strongly suggests a courier that specializes in diamond, gem and jewelry transport, with tracking and full insurance.

Once IGI receives a stone, the guide asks you to allow 5 to 8 business days for grading.

How do you check a report you've been handed?

If a seller hands you a report, check it with the laboratory that issued it, not through a link or document the seller supplies. Use the issuing lab's official website to find out how to verify the report. If the lab confirms report details, compare them with the copy you were given.

Then check the stone against the report:

• Shape and measurements. Do they match the stone in front of you?
• Carat weight. For a loose stone, ask how its weight was checked; for a mounted stone, ask the seller how it was matched to the report.
• Inscription. If the report mentions a laser inscription on the girdle, can you see it under a loupe?

A report describes one specific diamond. Check that its details match the stone you are buying.

If anything doesn't line up, stop and ask before you pay. The GIA laboratory on 47th Street can be reached on +1 212 221 5858. IGI's New York office is listed on its location page. And if you buy online, read the seller's returns policy before you order. Ours is at /policies/returns.

Using a report to spend less, not more

Whether a report comes from GIA on 47th Street or IGI on Fifth Avenue, use its findings alongside what you can see in the stone. Your eye only sees some of it. The most useful thing a report can do is show you where to stop paying.

• Clarity. Past the point where a diamond is eye-clean, a higher clarity grade buys you nothing you can see when the ring is on a hand.
• Color. In the near-colorless range, neighboring grades are hard to tell apart face-up, especially once the stone is set.
• Cut. Where the report provides a cut grade, give it attention; cutting has a major effect on how bright a diamond looks.
• Lab-grown versus natural. Lab-grown diamonds usually cost less than comparable natural ones. If two stones look the same, we'd recommend the lab-grown one.

Read the report to find the cheapest stone that looks the way you want, then stop there.

When you are ready to compare stones, the report is the tool. Where those grades are available, compare cut first, then choose color and clarity grades that look clean and white enough to you. Our center stones for engagement rings are a good place to try that.