Let’s find your perfect piece.

Leeser Diamonds Ring


Veteran expertise.

Leeser Diamonds is the offspring of renowned Dutch company Gassan Diamonds, where Guy Leeser learned the nuances of the industry from his grandfather, legendary diamantaire Samuel Gassan. Guy honed his craft for 31 years at Gassan before establishing his own company at the nexus of the diamond trade, Manhattan’s bustling Diamond District. Here, we share a roof with such industry authorities as the GIA in The International Gem Tower.

Perpetual personalization.

Samuel Gassan instilled in his grandson the virtue that delightful customer experiences are born of meaningful partnerships, not transactional relationships. Shopping with Leeser is a journey that begins with discovery and education: We’ll define your quintessential piece, then leverage our resources to locate the foremost options worldwide. And beyond your purchase, we’re here to ensure it remains properly snug and glowing.

A family affair.

Gassan’s legacy manifests in a business where his grandson and great-grandson, fourth-generation diamond savant Alex Leeser, uphold his core values to deliver exceptional customer experiences.

Attested trust.

“Guy and Alex are super knowledgeable, very kind, and very helpful.” The acclaim of those customers speak best to trust we’ve carefully garnered and passionately preserve.

A world of selection.

With his rising international stature, Guy formed relationships across the globe. Today, the world is our inventory. Your ideal piece may be an ocean away, but for us, it’s just a phone call.

Pricing power.

Leeser’s global network also affords us the purchasing power to command the best rates, which we happily pass on to our customers.

Cut diamonds,
not corners.

When it comes to quality, we keep it simple: Every Leeser stone is graded by the authoritative Gemological Institute of America, with comprehensive documentation.


“Great place for jewelry shopping! Guy and Alex are super knowledgeable, very kind, and very helpful. I got the engagement and wedding rings for my wife and I here. Everything is custom made and their jewelry options are seemingly endless.”

Five Stars

William Sheridan

Manhattan, NY

“My wife’s diamond wedding ring was handcrafted by Leeser Diamonds. We liked it so much, she got diamond earrings from Leeser Diamonds as well. And when it came time for our daughter to get married her wedding ring was from… Leeser Diamonds.”

Five Stars

Andrew Landorf

“Guy and Alex were so helpful!! Guy was so informative and helpful in the process since I knew just about nothing on the topic of jewelry. All of the custom work on the rings is stunning!”

Five Stars

Max Pachner

Hoboken, NJ

“Working with Alex was incredibly stress-free. From finding the perfect stone, to creating the setting, Alex and the jewelers went above and beyond with their craftsmanship and service.”

Five Stars

Andrew Lawson

“The whole process was incredibly seamless. His knowledge is unrivaled and you can be sure the quality of the product will be top notch.”

Five Stars

Robert Hutchins

“Guy helped to educate me on what makes a diamond special, but also helped guide me to the perfect diamond in my price range. He guided me through the entire process and was always patient and willing to answer all my questions. The ring turned out perfectly.”

Five Stars

Cyrus Blais

Visit CTA

Visit Leeser

At the heart of the diamond trade.

We’re located at the global nexus of the diamond industry—in Manhattan’s bustling Diamond District. In fact, we share a roof with the GIA, “the world’s foremost authority on diamonds,” who keeps our stones certified and our staff credentialed.

Schedule a visit →

Founder’s Note

My affinity for diamonds predates my first memory. As a young child in Holland, I marveled at their spectacular natural beauty while my grandfather showed me arrays of shapes and colors in his historic factory.

That visceral appreciation never left me. But today, my passion for diamonds lies in the delight they bring others.

Whether you’re shopping for a momentous life occasion or simply a personal reward, Alex and I can’t wait to guide you to a piece that will fulfill your vision with eternal joy.

Please introduce yourself by email or call us at (212) 371-1810 to begin the conversation.

Guy Leeser of Leeser DiamondsGuy Leeser Signature