Materials glossary / Standard and mark
Fineness (925, 750, 585)
On the label: Fineness · Standard and mark
What it is
Purity in parts per thousand, the European and silver convention: 925 is sterling, 750 is 18k, 585 is 14k, 950 is platinum.
Standard and marks: The marks, tests and laws behind the words on a label: karat stamps, UV400, ANSI Z80.3, the FTC Jewelry Guides, Prop 65.
Wikidata: Mass fraction of fine metal in a precious metal object. Q1401905 →
In the research
6 PubMed papers mention it with jewelry, allergy, eyewear or UV; the three most recent:
- Effective Picosecond Nd:YAG laser on seborrheic dermatitis and its mechanism · Journal of cosmetic dermatology, 2022
- Preparation of Nanomaterial Wettable Powder Formulations of Antagonistic Bacteria from Phellodendron chinense and the Biological Control of Brown Leaf Spot Disease · The plant pathology journal, 2021
- Affordable Thin Lens Using Single Polarized Disparate Filter Arrays for Beyond 5G toward 6G · Sensors (Basel, Switzerland), 2019
A paper is a paper, not a verdict: titles are listed so you can read them, and a study on one fabric or one filter says little about the piece in your hand.
Other standard and marks
Clasp & Lens describes materials from the public record and does not appraise, grade or test pieces; what a listing states is the supplier's statement. If a piece causes a rash, take it off; a reaction that spreads or blisters is a doctor's question, and sunglasses are no substitute for impact-rated eye protection where that is required.