Cinnabar
A toxic mercury sulfide mineral with a bright scarlet to brick-red color, rarely used as a gem.
Physical & Optical Properties
RI Range2.905–3.256
SG Range8.00–8.20
SG Typical8.10
Hardness (Mohs)2–2.5
Crystal SystemTrigonal
Optic CharacterDR Uniaxial (+)
Birefringence0.351
Dispersion0.400
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismStrong Dichroic
ColorsRed Pink, Brown
SpeciesCinnabar
Key Differentiators
- Extremely high specific gravity
- Vermilion red color
- Very low hardness and toxic (mercury)
Treatments
- Surface wax (on carvings)
Price Context
Natural — low ($/ct)$5
Natural — high ($/ct)$30
NotePer carat; rare collector gem; handle with care — mercury sulfide is toxic
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
About Cinnabar
A toxic mercury sulfide mineral with a bright scarlet to brick-red color, rarely used as a gem.
Identifying a cinnabar? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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