Fine silver (999)
On the label: Fine silver · Metal
What it is
99.9 percent silver. Used for bezels and some handmade pieces because it is easy to work; it bends and marks easily and tarnishes more slowly than sterling.
Metals: Solid metals: what the piece is made of all the way through. Purity is written as karat (gold) or parts per thousand (925 silver, 950 platinum).
Wikidata: Silver alloy with as high silver content as possible. Q1401994 →
In the research
No PubMed papers mention this material with jewelry, allergy or eyewear; that is usual for findings and trade terms.
Other metals
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.