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With humble roots from a non-gem trade family, as a lapidary hobbyist, Jeffery cut and polished his first gemstone at the age of fourteen launching him on a lifelong career that has taken him to more than 70 countries, and every continent except Antarctica. With 5 decades of broad-based experience in natural gemstones, diamonds, and fine jewelry, in 2020 Jeffery founded Eighth Dimension Gems (formerly Primagem) in Bangkok, Thailand, where he has lived for over 30 years.


Jeffery’s formal gemological training was accomplished at the prestigious SSEF - Swiss Gemmological Institute in Basel, Switzerland where he passed requisite exams for his SSEF Basic Gemmology (BGC) Diploma/Certificate, SSEF Basic Diamonds (BDC) Diploma/Certificate, and completed SSEF’s Advanced Pearls (ATC), Advanced Colored Stones (ATC) and Scientific Gemmology (SGC) courses.


Featured in many gem and jewelry periodicals, Jeffery has also appeared in interviews on the ABC, BBC, CCTV, CNA, CNN, NBC, and GEO. He has been quoted in Time, USA Today, National Geographic, Discover, GIA’s Gems & Gemology, Gem-A’s Journal of Gemmology, ICA’s InColor, Rivista Italiana di Gemmologia/Italian Gemological Review, and many other publications around the world. A guest speaker at eight GIA Gem Gatherings as well as many gemological conferences & universities, Jeffery is also an Honorary Professor for the AIGS – Asian Institute of Gemological Sciences in Bangkok, Thailand, and pro bono Vice President, Emeritus of the IGS - International Gem Society.

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