Serving the Diamond Industry with Unmatched Expertise

About GemSource Capital

GemSource Capital was founded to solve a real problem in the diamond trade.
Many jewelry businesses hold high-value, GIA-certified diamonds—but struggle to access liquidity. Traditional lenders often overlook the unique value of these assets, leaving a gap in financing where it’s needed most.

Rooted in New York City, the heart of the U.S. diamond market since the 1980s, GemSource Capital brings over 40 years of industry insight to a modern lending platform. We understand the dynamics of the trade and offer financing that respects the true worth of your inventory.

Our mission is to be the trusted bridge between jewelers and capital markets, delivering smart financial solutions that unlock opportunity, protect asset value, and support long-term growth.

Governance, Values, and Vision

GemSource Capital is led by a pioneer in the diamond industry whose career began in New York’s diamond district in the 1980s. With decades of experience and deep relationships across the global jewelry trade, our founder has earned the trust of iconic houses including Tiffany & Co., De Beers, Van Cleef & Arpels, and Harry Winston.

Our CEO brings a rare blend of industry expertise and global perspective—having worked with clients across cultures, headlined events alongside U.S. leadership, and served high-profile figures in fashion and music. This leadership is grounded in authenticity, discretion, and a deep understanding of the value diamonds hold—not just in the market, but in the businesses that trade them.

Meet the Team at GemSource Capital

  • Isaac Segall

    Managing Director

    The journey began with a bold leap, an unwavering commitment to excellence and a drive to redefine the diamond industry. Isaac is a distinguished figure in the diamond industry since the 1987. His illustrious career includes serving top diamond houses such as Tiffany, Van Cleef & Arpels, and Harry Winston

    Through decades of strategic leadership, he has forged strong partnerships with the world’s most respected diamond companies and jewelers. Isaac’s expertise is built on a legacy of innovation, trust, and a keen understanding of the market’s shifting landscape. A Summa Cum Laude graduate from New York University, Isaac holds both a B.S. and an MBA in Finance. Further, he is a two-time U.S. software patent holder, reflecting his multidisciplinary acumen.

  • Geffen Segall

    Lead of Lending Operations

    As the Lead of Lending Operations at GemSource Capital, Geffen has a proven track record in capital markets and fintech innovation that brings institutional-grade financing to the jewelry sector. He previously held roles at Emigrant Bank Capital Markets, IBM, and UBS, gaining deep experience in structured credit, derivatives, and financial technology. He holds a B.B.A. in Finance and International Business from The George Washington University, along with certifications in Bloomberg Analytics and Blockchain Consulting. Geffen is recognized for bridging traditional finance with next-generation fintech solutions.

Our Legacy of Excellence

Tracing over four decades of innovation, growth, and trusted partnerships in the diamond and jewelry sector.

  1. 1987 – Founding of Sol Capital Group (SCG)

    Established during post-Soviet market shifts, SCG leveraged liquidity gaps to build a foundation in manufacturing and diamond production with a focus on rare stones.

  2. 1988 – Gem Source International (GSI)

    Under Isaac Segall, GSI became a trusted supplier for Tiffany, Harry Winston, and Van Cleef & Arpels—renowned for precision and consistency in melee diamonds.

  3. 1995 – Launch of Ideal Cut Melee (ICM)

    ICM pioneered precision-cut standards using advanced Sarin technology, setting a new benchmark in ideal-cut melee production.

  4. 1999 – GemWorks NS LLC

    A joint venture delivering high-fidelity jewelry manufacturing for Tiffany & Co., achieving over $6M in sales with GSI-sourced stones.

  5. 2000 – Bryn Marcus Jewelry

    Formed to specialize in platinum diamond necklaces, utilizing consignment-based access to top-tier stones for exceptional craftsmanship.

  6. 2001 – M. Zak Jewelry

    A vertically integrated subsidiary expanding into natural diamond jewelry design and manufacturing, reinforcing end-to-end control.

  7. 2008 – Formation of GemSource ICM

    Amid the global banking crisis, SCG consolidated its cutting and distribution units to sustain efficiency and quality leadership.

  8. 2019 – Creation of GemSource Capital

    Launched to deliver specialized lending solutions for the global diamond trade—helping businesses stay liquid and competitive.