Calomel
Mineral Hg2Cl2
Also called Horn quicksilver
Take care.
- Contains mercury: Wash your hands after handling it, and never heat it: the fumes are poisonous.
- Fades or changes in light: Keep it in the dark, out of sunlight and bright display lights.
About it
Soft, sectile, adamantine crystals and crusts of mercury chloride that darken in light. Best known from Terlingua, Texas, and Moschellandsberg, Germany.
- Type
- Mineral
- Group
- Halide
- Formula
- Hg2Cl2
- Hardness (Mohs)
- 1.5–2
- Specific gravity
- 6.4–7.2
- Streak
- pale yellowish white
- Lustre
- adamantine (diamond-like)
- Crystal system
- Tetragonal
- Colours
- colourless, white, yellowish, grey, brown
- Transparency
- transparent, translucent
- Cleavage and fracture
- good prismatic; conchoidal fracture, sectile
- Under UV light
- often red-orange under UV
Typical values: real specimens vary. For more, see mindat.org.