American Gemological Appraisals & Gem Lab

About this Appraiser

American Gemological Appraisals and Gem Laboratory (AGA) is a premier, NAJA-accredited gemological laboratory located within the QCB Jewelers building in Whittier, California. The laboratory is owned and operated by Co-Directors Craig A. Sperling and Guillermo Oliva with 47 years of dedicated field experience in the jewelry and diamond trade.

Appraisal & Laboratory Services

AGA provides an efficient same-day appraisal service directly from our fully equipped Whittier laboratory, with no appointment necessary. Upon arrival, your items are personally examined by our gemologists and appraisers. The purpose, methodology and scope of work for your appraisal and or laboratory requirements are clearly discussed and established before any work begins.

For clients requiring maximum security, convenience or discretion, particularly those with high-value items, estate liquidations or large private collections. AGA offers a premium, on-site valuation service. We can bring our diagnostic capabilities directly to your residence, corporate office or law firm allowing evaluations to be performed safely in your presence.

Comprehensive Appraisal & Support

We provide expert valuation, grading and diagnostic reporting for all varieties of fine jewelry, including antique, period and contemporary pieces. Our laboratory routinely conducts assessments on loose or set:

• Diamonds (including advanced origin and treatment screening)
• Colored gemstones (utilizing advanced spectroscopy and diagnostics)
• Jade - Jadeite and Nephrite
• Fine pearl strands and jewelry
• Numismatic items and coins
• Watches - Vintage and modern high-end timepieces

Official Valuation and Consultation Formats

• Insurance Replacement Appraisals: For securing accurate coverage and post-loss protection.
• Fair Market Value Reports: For equitable distribution, IRS compliance, or resale.
• Probate, Trusts, & Estate Tax Documentation: Specialized reporting for estate executors and legal counsel.
• Divorce & Dissolution Settlements: Unbiased, independent asset division valuations.
• Liquidation & Charitable Donation Valuations: Tailored to meet strict regulatory deduction criteria.
• Advanced Gem Identification & Quality Grading: Scientific analysis and opinion of origin, treatment and authenticity.
• Expert Witness & Litigation Support: Professional dispute resolution, damage reporting, post-loss assessments and formal courtroom testimony.

Strict Regulatory Compliance

Every report generated by American Gemological Appraisals is presented in compliance with the strict ethical codes, methodology and reporting regulations laid down by USPAP (Uniform Standards of Professional Appraisal Practice) and the NAJA (National Association of Jewelry Appraisers).

AGA proudly serves private consumers, retail jewelers, manufacturers, wholesalers, arbitrators, banking institutions and law firms, fiduciaries, administrators, legal and judicial.

Need to schedule an evaluation or request support?

Please use the direct email and phone links at the top of this page to connect with our Whittier laboratory.