THE SHORT ANSWER
A fineness number is one field in a larger evidence record
Read every adjacent symbol before translating 375, 585, 750 or a karat mark. A construction qualifier can limit the gold claim to a layer; a sponsor, maker or trademark identifies responsibility; an assay-office mark can show independent testing in a recognized system. Jurisdiction, date, location and conflicts determine what the set can support.
MARK ANATOMY
Transcribe six kinds of evidence without rearranging them
U.S. AND UK EXAMPLES
Do not merge a trademark system with a hallmark system
The FTC consumer guide tells U.S. buyers to look near the karat mark for the name or U.S. registered trademark of the company standing behind it. GOV.UK identifies three compulsory elements of a full UK hallmark: sponsor or maker, metal-and-fineness, and assay office. These are related trust functions but not interchangeable legal systems.
For conversion between karats and parts per thousand, use the dedicated karat and fineness guide. This page instead asks whether the complete mark set supports the construction being sold.
CONFLICT PROTOCOL
Never erase a contradiction by choosing the nicer mark
- Photograph the mark in place and transcribe spacing, shapes and adjacent qualifiers exactly.
- Preserve the seller listing, invoice, repair record and claimed jurisdiction.
- Check an official assay office, trademark or hallmark reference appropriate to the date.
- Match the test to the dispute: surface, thickness, geometry, homogeneity or representative assay.
- Escalate unresolved conflicts before payment, destructive testing, repair or resale.
OFFICIAL SOURCES AND SCOPE
Construction words only work inside a defined jurisdiction
- The U.S. FTC consumer guide to platinum, gold and silver jewelry explains karat marks, solid and hollow construction, mechanical overlays, electroplate, vermeil, wash and the responsible company's mark. It was published in November 2024.
- The GOV.UK hallmark summary and practical guidance notes define the UK's complete hallmark, weight exemptions and special treatment of mixed, plated and filled articles.
- The UK's gold-plated silver description guidance explains why the underlying silver may be hallmarked while a standalone gold fineness mark can misdescribe the article.
- The Hallmarking Convention technical glossary distinguishes marks, screening and validated fineness determinations in the Convention system.
Sources reviewed July 31, 2026. Rules, terminology, exemptions and recognized marks vary by country and date. Verify the law and official assay-office guidance for the market where an item is described or sold.
FREQUENTLY ASKED QUESTIONS
Questions that change the answer
Is 585 the same as 14K?
Both are commonly used to communicate a gold-alloy fineness near 58.5 percent, but legal tolerances, mark forms and accepted standards depend on jurisdiction. Use the karat-fineness guide for conversion, then interpret the complete mark set.
What makes a full UK hallmark?
GOV.UK identifies three compulsory components: sponsor or maker's mark, metal-and-fineness mark, and assay-office mark. A date letter is optional.
What do GP, GF and RGP mean?
They are commonly used U.S. construction qualifiers for plated, gold-filled and rolled-gold-plate descriptions. Their evidentiary value depends on the complete adjacent designation, responsible party, jurisdiction and item.
What should I do when a mark conflicts with a test?
Preserve both observations, stop any irreversible transaction, verify the correct testing scope and mark interpretation, and escalate to a qualified independent reviewer instead of choosing the convenient result.