About SEQUOIA
Sequoia Gem Services is led by Graduate Gemologists with over 30 years of combined experience in jewelry appraisal, diamond grading, and high-end gemstone evaluation.
Our background spans global sourcing, design, grading, and investment-level jewelry, allowing us to provide accurate, transparent appraisals for a wide range of clients and purposes.s and purposes.
Experienced Jewelry Appraisers
You Can Trust
Experienced Jewelry Appraisers
You Can Trust
ABOUT US
ABOUT US
A Personalized & Transparent Approach to Jewelry Appraisals
Maddison Armstrong, GIA GG
Graduate Gemologist | NAJA Member
Memberships
Maddison is a classically trained gemologist with a background in diamond grading, jewelry design, and high-end evaluation. She studied at the Gemological Institute of America and began her career grading diamonds at the GIA before expanding into design, custom work, and investment-grade jewelry.
Her experience includes global sourcing and manufacturing projects in Bangkok, Dubai, Hong Kong, and Qatar, along with over 15 years of hands-on work across multiple areas of the jewelry industry.
• National Association of Jewelry Appraisers (NAJA)
• GIA Alumni Association
Professional
Education
• Graduate Gemologist (GIA, 2015)
• Accredited Jewelry Professional (2014)
• Jewelry Design & Technology (2014)
• Diamond Grading & Evaluation (2015)
• Colored Stone Identification (2015)
Professional
Background
• Owner, Sequoia Gem Services (2025–Present)
• Head Buyer, SH Silver Company (2021–2025)
• GIA Diamond Grader (2015–2016)
Henry is a Graduate Gemologist with over 15 years of experience in jewelry appraisal, diamond grading, and high-end inventory management. He began his career grading diamonds at the Gemological Institute of America before moving into leadership roles in wholesale operations and estate jewelry purchasing.
His recent work has focused on ultra-high-end colored stones, rare diamonds, and luxury watches for private clientele, bringing a refined and highly specialized perspective to each appraisal. jewelry industry.
Henry Chaplin, GIA GG
