Calomel & Mercury

expanded, factual, no speculation beyond what is known):

Calomel & Native Mercury – Landsberg, Obermoschel, Donnersbergkreis, Rhineland-Palatinate, Germany

Rare and historically significant calomel associated with native mercury on matrix from the classic Landsberg locality near Obermoschel, Donnersbergkreis, Rhineland-Palatinate, Germany. The specimen shows greyish to brownish translucent calomel occurring together with metallic, dark silvery native mercury, preserved within the altered host rock.

Calomel (Hg₂Cl₂) belongs to the halide mineral group and forms as a secondary mercury mineral, typically under near-surface conditions through the alteration of primary mercury-bearing phases. Native mercury is a very uncommon companion mineral, making such combined specimens particularly desirable among advanced collectors.

The Obermoschel–Landsberg area is a historic mercury locality in Germany, well known for classic mercury minerals such as calomel, cinnabar, and native mercury. Most material originates from old workings and was collected after mining activity, often from dumps and altered zones.

Calomel is considered rare on a global scale, and specimens showing a clear association with native mercury are especially scarce. The mineral is sensitive to light, heat, and mechanical stress and should be stored carefully, ideally protected from strong light and temperature fluctuations.

Typical associated minerals at this locality include cinnabar, native mercury, gypsum, quartz, and various secondary mercury chlorides and oxides.