Cinnabar
Mercury Sulfide (Cinnabar) · Mineral Specimen / Toxic Ore
Crystal System
Trigonal (Hexagonal scalenohedral); typically massive, granular, or earthy; rarely found as distinct rhombohedral crystals.
Mineral Group
Sulfides
Chemical Formula
HgS (Mercury II Sulfide) - often containing impurities of iron, clay, or organic matter.
Formation Process
Hydrothermal; forms as veins or impregnations near recent volcanic activity and hot springs at low temperatures (below 200°C).
About This Crystal
An opaque to semi-translucent mineral specimen approximately 2cm in size. It displays a characteristic cochineal to brick-red color with an earthy, dull luster. The specimen appears granular and massive, seated on a dark, rocky matrix.
Physical Characteristics
Color: Bright red to brownish-red; Streak: Scarlet/Red; Cleavage: Perfect rhombohedral (rarely seen in massive form); Fracture: Subconchoidal to uneven; Specific Gravity: Very high (~8.1); Magnetism: None; Fluorescence: None.
Optical Properties
High Refractive Index (approx. 2.90–3.20); Uniaxial positive; Extremely high birefringence; often too opaque in massive form to show typical optical phenomena.
Hardness & Durability
Origin Region
Almadén (Spain), Idrija (Slovenia), and various locations in China (Hunan, Guizhou); typically found in volcanic and shallow hydrothermal environments.
Hardness & Durability
Mohs Hardness: 2.0 to 2.5 (very soft, can be scratched by a fingernail). Toughness: Very brittle. Toxicity: Specimen contains Mercury and is hazardous if inhaled or ingested.
Care & Maintenance
Wash hands immediately after handling. Store in a sealed container or display case to prevent dust inhalation. Keep away from heat sources as it can release toxic mercury vapor. Clean only with a dry brush; avoid ultrasonic cleaning.
Rarity & Value
Moderately common as an ore but high-quality crystalline specimens are rare. Value is generally low for earthy fragments like this ($5-$15 USD), but high for fine crystals.
Special Characteristics
High density (feels surprisingly heavy for its size). It is the primary ore of Mercury. When heated, it decomposes to release elemental mercury.
Lore & History
Historically known as 'dragon's blood' and used as the pigment 'vermilion' in ancient art and calligraphy. It was used in Chinese alchemy for 'elixirs of immortality' and is associated in traditional lore with the Root Chakra and vitality; however, its mercury content makes it medically dangerous.