Diamond Valuation At The RealReal
Diamond Valuation At The RealReal

Meet the Man Who Handles $1m in Diamonds a Week

Words by Jody Hume | 6.9.16
On the heels of recent openings in New York, Los Angeles and Chicago, our fourth Fine Jewelry & Watch Valuation Office is officially open for business in our home city of San Francisco. Located in the penthouse of our new HQ building, it’s another lovely space to visit and find out the true resale value of the most special pieces in your jewelry box. And it’s there you will meet our Graduate Gemologist and SF Valuation Manager, Sean Johnson. With a wealth of experience that spans everything from top auction houses to fair-trade gold mining, he’s seen an impressive array of fine gems, making him an expert uniquely suited to his new position. Here, we asked him to share what got him into gemology, the ins and outs of diamond valuation, how many pieces he sees come through the office each week, and the most stunning piece he’s ever encountered (hint: it’s record-breaking).
What is your background in gemology and horology? What made you interested in a career in this field?
Having been born and raised in Geneva, Switzerland, the epicenter of horology and the city in which some of the world’s most renowned jewels are retailed on rue du Rhône or sold by major auction houses, I was drawn to the luxury goods business from a young age. While at university in the U.S., I performed an independent study on luxury products consumption in emerging markets and won a grant to research Brazil’s gem mines-to-retail ecosystem. Also while in college, I interned at an ecologically green, fair-trade gold mining company in the Chocó region of Colombia, which sensitized me to the ethical issues in gold trading. Later, in Southeast Asia, I spent most of my vacation going to auctions and gem fairs in Singapore and in Burma got a sense of the complexities of the ruby trade.
The RealReal Diamond Valuation Office
The San Francisco Valuation Office
8.35 carat cushion-cut diamond
Upon graduating, I immediately enrolled in the Gemological Institute of America (GIA) in Carlsbad, California, obtaining my Graduate Gemologist degree that same year. Since then, prior to joining The RealReal I worked in roles of increasing responsibility for several firms, at which I authenticated, bought and sold diamonds, jewelry, and watches, as well as participated in trade shows from Geneva to Hong Kong, Barcelona to New York.
So I’ve tried to keep expanding my skill set – gemological knowledge, valuation, foreign languages, commercial instincts, and customer interface – while building on relevant experience. All of which I now employ to meet The RealReal’s high standards.
Diamond Valuation At The RealReal
Sean inspects one of the most stunning diamonds we’ve ever listed on the site.
What are some of the most stunning pieces you’ve seen?
Prior to joining The RealReal I worked for Sotheby’s, where I was exposed to some of the most fabulous jewelry creations in the world. I was one of the lucky few able to feel and touch the Blue Moon – a 12.03 carat, Fancy Vivid Internally Flawless blue diamond, which will probably be one of the most stunning diamonds I will ever see. A short time later it was auctioned for $48 million, setting the world record for the most expensive diamond ever sold.
How many pieces do you see in a typical day or week?
Anywhere from 200 to 600 pieces a week.
Diamond & Watch Valuation At The RealReal
Tools of the trade.
How do you determine the market price of a diamond?
Lorraine Schwartz chandelier earrings
The intrinsic value of a diamond is based on the correlation between the 4C’s (carat, color, cut, clarity) established by the Gemological Institute of America, and the current market demand for that particular stone. Rarity, brand name, provenance, condition — these are also factors that will affect its price.
Additionally, I use internal and external databases to help guide me through the valuation of a diamond, as well as a network of highly competent colleagues across the country from whom I can receive feedback instantaneously. And as necessary, we will send pieces to the GIA labs for verification.
Why do you hear different prices from different people?

The diamond industry remains one of the most opaque industries in the world, where many traders and companies take advantage of the customers’ relative lack of knowledge.
David Yurman diamond x cable bracelet
Here at The RealReal we are able to list pieces at the highest possible price with complete transparency, as we have no incentive to undervalue an item. I like to view our consigning clients as our partners as we work together to achieve the highest possible price that will clear the market.  
What is the best way to get top resale value for your diamonds and other fine jewelry pieces?
I always advise potential sellers to bring all of the documents related to the pieces they are interested in consigning, including GIA reports, Extract from the Archives, watch boxes, purchase receipts, etc. People often underestimate the importance of these documents.
I also encourage our clients to do their own due diligence by educating themselves about the market value of their piece. They quickly discover that The RealReal consistently offers the highest marketable value for their pieces, as we eliminate the middleman and sell directly to the end consumer – four and a half million active buyers on our platform and growing.

Diamond Valuation At The RealReal

Are diamonds a good investment? When is a good time to sell?
One big misconception is that diamonds are good investments. In reality less than 1% of the diamonds in the world have the potential to appreciate as a capital asset in a portfolio. Unless you are a genuine expert and have the resources (and patience) to invest in those truly investment-grade stones, my advice would be to buy what you love, wear it, and when you no longer have emotional attachment towards it, consider selling it, and using the proceeds to buy a new (or pre-owned) piece that you enjoy even more!
What’s your favorite part of the job?
18K diamond and yellow sapphire earrings
I really do love every facet of my work. It’s hard to complain when I have the opportunity to see exquisite jewelry and watches on my desk every day!


Part of my job is to educate our clients about their pieces, and I feel privileged when I can satisfy our customers’ inquiries. To me, every piece of jewelry has a story to tell, and everyone has a different reason for selling their jewelry or watches. One of the best parts of my work is learning about people’s lives through the stories of their jewels.
What’s the dream piece you’d love to see come into the office?
That is a tough question! I would love to see an Art Deco tutti frutti bracelet, or a piece — also from the 1920s — celebrating the revival of interest in all things Egyptian, following the discovery of Tutankhamun’s tomb. Those pieces are exquisite and truly represent the essence of jewelry making from that heady decade. Within the watches category, an eighteenth century musical automaton singing bird cage clock would make my day. Such clocks represent the foundation of modern horology; they are rare and highly sought after.

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