Arsenic
Native Arsenic · Mineral Specimen / Native Element
Crystal System
Trigonal; typically found as botryoidal, massive, or reniform (kidney-like) habits, rarely as distinct rhombohedral crystals.
Mineral Group
Native Elements (Arsenic Group)
Chemical Formula
As (with trace Sb, Fe, Ni, Ag, S)
Formation Process
Hydrothermal; typically formed in medium and low-temperature hydrothermal veins alongside lead, silver, and cobalt ores.
About This Crystal
The specimen displays a metallic luster with a lead-gray to tin-white color on fresh surfaces, which quickly tarnishes to a dull dark gray or black. It shows a granular to massive surface texture with typical curved, concentric layering.
Physical Characteristics
Color: Tin-white fresh, black tarnish. Streak: Gray. Cleavage: Perfect on {0001}. Fracture: Uneven. Density: 5.72–5.83 g/cm³. Brittle. Odor: Garlic-like when crushed or heated.
Optical Properties
Opaque with a high metallic luster. Under reflected light microscopy, it shows white to yellowish-white color with strong anisotropy.
Hardness & Durability
Origin Region
Sachsen, Germany (Schneeberg); Bohemia, Czech Republic; Akatani mine, Japan; and British Columbia, Canada. Found in hydrothermal veins.
Hardness & Durability
Mohs hardness 3.5. Very brittle and fragile. Sensitive to oxidation; can degrade physically over time into powder.
Care & Maintenance
Extremely toxic. Store in a sealed, labeled container away from children/pets. Wash hands thoroughly after handling. Clean with dry methods only; avoid acids and heat.
Rarity & Value
Relatively rare as a native element. Value is moderate for well-formed botryoidal specimens, primarily sought by mineral collectors specializing in native elements.
Special Characteristics
Gives off a strong, characteristic garlic odor when struck or heated (toxic arsenic trioxide gas). Rapidly tarnishes (pseudo-allotriomorphic).
Lore & History
Historically associated with the production of pigments (orpiment/realgar) and poisons. In alchemy, it was represented by a swan. It has long been associated with toxicity more than traditional healing lore.