Materials glossary / Standard and mark
Karat (k, kt)
On the label: Karat · Standard and mark · a rule or standard applies
What it is
The US purity scale for gold: parts of gold in 24. 24k is pure, 18k is 75 percent, 14k is 58.3, 10k is 41.7 (the legal minimum to be sold as gold). Stamped on the piece with the maker's mark.
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: Unit of mass (200 mg). Q261247 →
In the research
3 PubMed papers mention it with jewelry, allergy, eyewear or UV; the three most recent:
- [Determination of Ni and Pd in white karat gold jewellery by the EDXRF extrapolate-regression method] · Guang pu xue yu guang pu fen xi = Guang pu, 1998
- Sensitivity to gold ball orbital implant; eczematous contact dermatitis due to 14 karat gold; report of a case · Archives of ophthalmology (Chicago, Ill. : 1929), 1950
- A case of sensitivity to gold-ball orbital implant; eczematous contact-type dermatitis due to 14-karat gold · American journal of ophthalmology, 1949
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.
Pieces whose listing names it
12 on the siteMatched from the words in the supplier's listing; the full material line is on each product page.
Made in the USA
Made in the USA
Made in the USA
Made in the USA
Made in the USA
Made in the USA
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.