About GCAL

Gem Certification and Assurance Lab (GCAL) is a diamond research and identification laboratory specializing in guaranteed diamond grading:

  • A subsidiary of Collectors Universe (NASDAQ:CLCT), founded in 1986 and publicly-traded since 1999.
  • Research led by a PhD in mineralogy experienced in the detection and identification of treatments and synthetics.
  • Employs some of the top experts in the diamond grading industry.
  • Equipped with state-of-the-art technologies and instrumentation, including the DTC DiamondSure, DTC DiamondView, FTIR Infrared Spectrophotometer and Raman Spectrometer. Take our virtual tour.
  • Located in New York’s diamond building

    580 Fifth Avenue LL
    New York, NY 10036
    Telephone: 212-869-8985

GCAL is the only diamond grading company:

  • With a "Zero Tolerance" Consumer Grading Guarantee that provides cash-back for any error in grading or identification of the certified diamond. See Guarantee
  • That is part of a public company. In the last fiscal year, Collectors Universe graded over 3.2 million items valued at approximately $1.8 billion.
  • With public financial reports, audited internal controls, and subject to regulation by the United States Securities and Exchange Commission.
  • That has access to capital markets through Collectors Universe. The Board of Directors of Collectors Universe has fully committed to deploying cash resources for the continued expansion into the diamond market.
  • That can be owned through the NASDAQ as a part of publicly-traded Collectors Universe. Any sight-holder, dealer, retailer or even retail customer has the opportunity to own publicly traded shares that represent part ownership of GCAL. Investor Information

GCAL Experts

Donald A. Palmieri Donald A. Palmieri
President, Gem Certification and Assurance Lab (GCAL), Master Gemologist Appraiser®

Expertise: Diamonds and Colored Gemstones.
Other Areas: Antique and Period Jewelry.


Maria Mrozek Maria Mrozek
Senior Gemologist, Gem Certification and Assurance Lab (GCAL)

Expertise: Diamonds.
Other Areas: Diamond Rough.
Jennifer Vichinsky Jennifer Vichinsky
Senior Gemologist, Gem Certification and Assurance Lab (GCAL)

Expertise: Diamonds.
Other Areas: Colored Stones.
Sharrie Woodring Sharrie Woodring
Senior Gemologist, Gem Certification and Assurance Lab (GCAL)

Expertise: Diamonds and Colored Gemstones.