Cinnabar
Cinnabar (Mercury(II) sulfide) · Mineral Specimen / Toxic Mineral
Crystal System
Trigonal; typically occurs in massive, granular, or earthy habits, sometimes showing rhombohedral crystals.
Mineral Group
Sulfides
Chemical Formula
HgS
Formation Process
Hydrothermal; forms in veins and impregnations near volcanic activity or alkaline hot springs at low temperatures.
About This Crystal
Bright scarlet to brownish-red earthy mass. This specimen shows a coppery-red to vermillion coloration with a dull to sub-metallic luster on the grainy surfaces and small sparkly crystalline faces.
Physical Characteristics
Color: Scarlet to brownish-red; Streak: Scarlet; Cleavage: Perfect rhombohedral; Fracture: Subconchoidal to uneven; Specific Gravity: 8.1; Fluorescence: None.
Optical Properties
Refractive Index: 2.905–3.256; Extremely high birefringence; Uniaxial positive; Adamantine to dull luster.
Hardness & Durability
Origin Region
Almadén (Spain), Huancavelica (Peru), Guizhou (China), and California (USA). Found in volcanic rocks and hot spring deposits.
Hardness & Durability
Mohs Hardness: 2.0–2.5; Very soft and brittle; Low durability; High toxicity due to mercury content.
Care & Maintenance
DANGER: Contains mercury. Do not inhale dust, do not ingest, and wash hands after handling. Store in a sealed container away from heat. Clean only with a dry cloth.
Rarity & Value
Relatively common but high-quality crystalline specimens are rare; Value is based on color intensity and crystal size; Often used as an ore of mercury.
Special Characteristics
Known for its extreme density (very heavy for its size) and its historical use as the primary pigment 'Vermillion'.
Lore & History
Used since antiquity as a pigment and in alchemy. In traditional lore, it is associated with transformation and wealth, though its high toxicity makes it dangerous for healing practices.