Obsidian
On the label: Obsidian · Gemstone
What it is
Natural volcanic glass, black or banded, Mohs 5 to 5.5; sharp-edged when broken and easily scratched.
Gemstones: Natural gemstones, as mined and cut. Hardness (Mohs scale) says what scratches what; treatment (heat, oil, dye) must be disclosed under FTC rules.
Wikidata: Naturally occurring volcanic glass. Q53754 →
In the research
2 PubMed papers mention it with jewelry, allergy, eyewear or UV; the three most recent:
- The analysis of release and percolation rate of nutrients from regular and obsidian-based slow-release fertilizers · Environmental monitoring and assessment, 2024
- A cryptoendolithic community in volcanic glass · Astrobiology, 2009
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
2 on the siteMatched from the words in the supplier's listing; the full material line is on each product page.
Other gemstones
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.