Fettelite, also known as sanguinite, is a mercury-

sulfosalt mineral Sulfosalt minerals are sulfide minerals with the general formula , where *A represents a metal such as copper, lead, silver, iron, and rarely mercury, zinc, vanadium *B usually represents semi-metal such as arsenic, antimony, bismuth, and rarely ...

with the chemical formula Ag₁₆HgAs₄S₁₅. The mineral was first described by Wang and Paniagua (1996) who named it after M. Fettel, a German field geologist who collected the first samples from

Odenwald The Odenwald () is a low mountain range in the German states of Hesse, Bavaria and Baden-Württemberg. Location The Odenwald is located between the Upper Rhine Plain with the Bergstraße and the ''Hessisches Ried'' (the northeastern section ...

. It was first collected in the Nieder-Beerbach mine, 10 km south of

Darmstadt Darmstadt () is a city in the state of Hesse in Germany, located in the southern part of the Rhine-Main-Area (Frankfurt Metropolitan Region). Darmstadt has around 160,000 inhabitants, making it the fourth largest city in the state of Hesse ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

. Its normal occurrence is in

hydrothermal vein In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved ...

s, which can cut

gabbro Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ...

diorite Diorite ( ) is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-sil ...

intrusives. It is closely related to other rare minerals like dervillite, daomanite, vaughanite and criddleite which are also found in the same type locality as fettelite. Fettelite occurs as clusters of hexagonal flakes. These flakes can get up to 0.2 mm across and around 5-10 µm thick. In more complex hexagonal tablets, somewhat larger sub parallel aggregates can be measured. Mandarino, J.A (1997) Abstracts of new mineral description The Mineralogical Record, 28, 141-143. The birefringence of Fettelite is moderate white to grayish brown.

References

Arsenic minerals Mercury(II) minerals Silver minerals Sulfosalt minerals Monoclinic minerals Minerals in space group 5 Minerals described in 1996 {{sulfide-mineral-stub