Baumhauerite is a rare lead

Lead

Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

 sulfosalt mineral. It crystallizes in the triclinic system

Crystal system

In crystallography, the terms crystal system, crystal family, and lattice system each refer to one of several classes of space groups, lattices, point groups, or crystals...

, is gray-black to blue-gray and its lustre

Lustre (mineralogy)

Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....

 is metallic to dull. Baumhauerite has a hardness

Mohs scale of mineral hardness

The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German geologist and mineralogist Friedrich Mohs and is one of several definitions of hardness in...

 of 3.

Baumhauerite occurs as small crystals embedded in dolomitic

Dolomite

Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....

 marble

Marble

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

. It is found primarily in the Lengenbach Quarry

Lengenbach Quarry

The Lengenbach Quarry is located in the Binn Valley and it is noted among the mineralogical community for its unusual sulfosalt specimens.-Location:...

, Binnental, in the Valais

Valais

The Valais is one of the 26 cantons of Switzerland in the southwestern part of the country, around the valley of the Rhône from its headwaters to Lake Geneva, separating the Pennine Alps from the Bernese Alps. The canton is one of the drier parts of Switzerland in its central Rhône valley...

 region of Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

, the mineral is named after German mineralogist Heinrich Baumhauer (1848–1926), who discovered it at Lengenbach, famous among mineralogists for its array of rare minerals, in 1902. Baumhauerite has also been reported at Sterling Hill, New Jersey

New Jersey

New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, typically in association with molybdenite

Molybdenite

Molybdenite is a mineral of molybdenum disulfide, MoS2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms...

, and in aggregates at Hemlo, Thunder Bay

Thunder Bay

-In Canada:Thunder Bay is the name of three places in the province of Ontario, Canada along Lake Superior:*Thunder Bay District, Ontario, a district in Northwestern Ontario*Thunder Bay, a city in Thunder Bay District*Thunder Bay, Unorganized, Ontario...

, Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

.