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DJR Expert Guide Series, Vol. 282 — Numismatic Forgery Lab Techniques: Plugged & Altered Coins
Plugged and altered coins are among the most deceptive—and financially damaging—forms of numismatic fraud. Modern forgers no longer rely on crude filling or surface filing. Today’s alterations involve alloy-matched metal plugs, micro-welding, laser resurfacing, ultrasonic texturing, chemical oxidation, and advanced re-engraving techniques engineered to conceal evidence at the microscopic level. Because these alterations disrupt metal flow, grain structure, rim geometry, and surface chemistry, proper detection requires a forensic examination far beyond the capabilities of casual magnification.
DJR Expert Guide Series, Vol. 282 — Numismatic Forgery Lab Techniques: Plugged & Altered Coins provides the complete authentication workflow used by professional examiners and laboratories. This guide explains how to identify filled holes, altered mintmarks, added metal, recarved numerals, reprofiled rims, artificial toning, and microscopic inconsistencies that reveal modern tampering.
Inside, you’ll learn how experts:
Detect plugged holes using grain disruption, texture mismatch & seam analysis
Identify altered mintmarks, added pieces, removals & transplanted mintmark discs
Evaluate surface planarity, micro-scratches, abrasion patterns & laser resurfacing
Reveal welding seams, filler metals & subtle heat distortion
Distinguish genuine die-struck relief from re-carved or added detail
Compare die states to known certified examples to spot inconsistencies
Use XRF to detect alloy mismatches & foreign trace elements
Identify artificial toning used to mask repairs or plugs
Analyze rims and edges for disrupted reeding, flat zones & heat discoloration
Detect reengraved dates, corrected numerals & recut serifs under magnification
Use forensic lighting methods including low-angle, polarized & UV illumination
Understand value impact, disclosure requirements & certification limitations
Volume 282 provides a complete lab-grade detection system—empowering collectors, appraisers, and dealers to identify even highly sophisticated numismatic alterations and protect themselves from costly forgeries.
Digital Download — PDF • 7 Pages • Instant Access
Plugged and altered coins are among the most deceptive—and financially damaging—forms of numismatic fraud. Modern forgers no longer rely on crude filling or surface filing. Today’s alterations involve alloy-matched metal plugs, micro-welding, laser resurfacing, ultrasonic texturing, chemical oxidation, and advanced re-engraving techniques engineered to conceal evidence at the microscopic level. Because these alterations disrupt metal flow, grain structure, rim geometry, and surface chemistry, proper detection requires a forensic examination far beyond the capabilities of casual magnification.
DJR Expert Guide Series, Vol. 282 — Numismatic Forgery Lab Techniques: Plugged & Altered Coins provides the complete authentication workflow used by professional examiners and laboratories. This guide explains how to identify filled holes, altered mintmarks, added metal, recarved numerals, reprofiled rims, artificial toning, and microscopic inconsistencies that reveal modern tampering.
Inside, you’ll learn how experts:
Detect plugged holes using grain disruption, texture mismatch & seam analysis
Identify altered mintmarks, added pieces, removals & transplanted mintmark discs
Evaluate surface planarity, micro-scratches, abrasion patterns & laser resurfacing
Reveal welding seams, filler metals & subtle heat distortion
Distinguish genuine die-struck relief from re-carved or added detail
Compare die states to known certified examples to spot inconsistencies
Use XRF to detect alloy mismatches & foreign trace elements
Identify artificial toning used to mask repairs or plugs
Analyze rims and edges for disrupted reeding, flat zones & heat discoloration
Detect reengraved dates, corrected numerals & recut serifs under magnification
Use forensic lighting methods including low-angle, polarized & UV illumination
Understand value impact, disclosure requirements & certification limitations
Volume 282 provides a complete lab-grade detection system—empowering collectors, appraisers, and dealers to identify even highly sophisticated numismatic alterations and protect themselves from costly forgeries.
Digital Download — PDF • 7 Pages • Instant Access