Gemologists have long used machines in diamond grading but technology has made it possible for them to “learn” how to do it on their own.
29-Carat D-Color Diamond Breaks Online Auction Record
It sold for $2.1 million at Christie’s online-only jewelry auction, which ended Tuesday.

New York—The largest D-color diamond to be auctioned via the internet is now the most expensive jewel ever sold at an online-only auction.
The 28.86-carat D-color, emerald-cut, VVS1 Type IIa diamond just exceeded its high estimate selling for $2.1 million at Christie’s Jewels Online sale concluded Tuesday.
Overall, the auction sold 100 percent by value and 93 percent by lot, with 64 percent of lots topping their high estimates.
Christie’s said the D-color diamond began receiving bids as soon as the sale commenced on June 16, earning a total of 31 bids from four countries spanning Asia to America.
Overall, the jewelry auction’s bidders spanned 27 countries and five continents, while daily online engagement was up 70 percent from the June 2019 Jewels Online sale.
Other noteworthy jewels include four pieces from Graff that were the second, third, fourth and fifth most expensive lots sold: a 46.57-carat cascading round diamond necklace that earned $275,000; a 40.86-carat “Ladygraff” diamond watch that sold for $175,000; a “Butterfly” pink sapphire and diamond watch that earned $150,000, triple its low estimate; and a diamond and sapphire necklace that fetched $87,500.
Christie’s International Head of Jewelry Rahul Kadakia noted of the headlining diamond: “The sale of this exceptional stone established the record for a jewel sold in an online-only auction, demonstrating greater client confidence in Christie’s digital ability and online sale platform.
“We now look forward to the beginning of our live auction season for jewelry spanning all major Christie’s global sale sites, led by a $8 million fancy intense blue IF diamond of 12.11 carats offered in Hong Kong on July 9.”
Christie’s first in-person sale following the disruption caused by COVID-19 will be its Fine Jewels sale July 8 in Paris.
Following the July 9 Hong Kong sale, Christie’s will hold Magnificent Jewels sales in Geneva and New York this month, as well as an Important Jewels sale in London.
The auction house also has three online-only jewelry and timepiece sales slated for July: Diamonds That Care from July 3-13; 101 Cartier Clocks from July 7 to 21; and Jewels Online from July 22 to Aug. 6.
The Latest

Supplier Spotlight Sponsored by IGI

Watch retailers Jeffery Bolling and Bobby Bengivengo discuss employee training, customer education and the sticky subject of future value.

The most trusted diamond report, available in print or the GIA App.

The company has plans to revamp the Movado brand and offer less expensive watches this year.


Sponsored by Noam Carver

As cybercrime incidents threaten the industry, jewelers need to know what they’re up against and the best ways to protect their businesses.

Navigate origin determination with Continuing Education seminars offered by the GIA Alumni Collective™.

The Pittsburgh jeweler is redoing the lighting and showcases, and adding a full hospitality bar as well as new shop-in-shops.

The Yurman Family Crystalline Pass is inside the museum’s brand-new Richard Gilder Center.

Zale has more than 40 years’ experience in the diamond industry, including 17 years as Stuller’s VP of diamonds and gemstones procurement.

The Strip is full of new restaurant and entertainment offerings.

National Jeweler’s senior editor covering fashion, trends, and design highlights the latest looks in the market.

From what ChatGPT is to how to use it, this is the explainer tailored to jewelers.

When it comes to pricing jewelry repairs, you should start by asking a simple question about the piece at hand, Peter Smith writes.

The industry veteran will serve as the diamond jewelry supplier’s head of business development.

He is the company’s new senior vice president of sales and business development.
The Tennessee school’s CAD Academy is now offering training in Gemvision’s MatrixGold software.

Blackstone is buying the 80 percent stake in the lab owned by a Chinese company as well as the 20 percent held by the Lorie family.

In a collection of Q&As, key players give insight on supply, demand, the importance of origin, and whether the “Color of the Year” matters.

The company confirmed it will be combining the auctions for the fifth and sixth sales cycles into one.

Among other changes, Stanley Zale, the former vice president of diamonds and gemstones, is leaving the company after 17 years.

One new addition was announced at the Conclave membership breakfast.

The 28-piece collection is the largest to be offered at auction.

The deal could be signed as early as this weekend, according to a report by The Economic Times.

It’s an ultra-luxurious version of the designer’s signature style.

Four guests join Michelle Graff and Amanda Gizzi to discuss the importance of being organized and what shoes they wear at the shows.