Emerald
On the label: Emerald · Gemstone · a rule or standard applies
What it is
Green beryl colored by chromium or vanadium. Mohs 7.5 to 8 but brittle and almost always included; most are oiled to hide fractures, which must be disclosed. Keep away from ultrasonic cleaners and heat.
Gemstones: Natural gemstones, as mined and cut. Hardness (Mohs scale) says what scratches what; treatment (heat, oil, dye) must be disclosed under FTC rules.
In the research
60 PubMed papers mention it with jewelry, allergy, eyewear or UV; the three most recent:
- Emerald Touchless Sensor Quantifies Nighttime Scratching and Sleep Quality in Children With Atopic Dermatitis: PEDISTAD EMERALD Study · Dermatology and therapy, 2026
- Spectroscopic and geochemical fingerprints for chromophore identification and origin determination of Davdar emeralds from Xinjiang, China · Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2027
- Orthokeratology for stable mild-to-moderate keratoconus: a pilot study on safety and corneal remodeling via quantitative OCT analysis · International ophthalmology, 2026
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
4 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
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.