The Black Range

Wulfenite, PbMoO4
From the Petroglyph Mine, Hillsboro Mining District, Sierra County, N.M.
 Specimen at Mineral Museum New Mexico Institute of Mining and Technology Socorro, New Mexico
Photograph taken on April 6, 2016

Wulfenite, Pb(MoO4), is a lead molybdate mineral which is often found in granular masses.  If you are a chemistry buff, it is the “molybdate” description which will raise your interest.  Molybdenum is a very flexible element and oxidizes in several different forms.  In fact it is not found in a pure state naturally on Earth but rather is always found in one of its oxidized forms.  The specimens of Wulfenite shown here are from the Macy (Vanadinite) Mine, and other locations, in the Hillsboro Mining District of Sierra County, New Mexico.

In my entry on Vanadinite I referred to the “clinal” nature of many chemical compositions.  The term in mineralogy is “series”.  As in “Wulfenite forms a series with the rarer mineral Stolzite, which contains tungsten in place of the molybdenum.”

The Wulfenite specimen shown below is from the Petroglyph Mine in the Hillsboro Mining District.  This mineral is only a minor ore of lead and molybdenum but its beautiful crystal structure makes it highly prized by collectors.

Many minerals were not named until the 1700’s and 1800’s.  Wulfenite received its current name in 1845, for instance.  (Its original name - given in 1772 - was “plumbum spatosum flavorubrum, ex Annaberg, Austria”.

This is a partial listing of mines where Wulfenite was found in the Black Range:

HILLSBORO DISTRICT: Big Chief Mine in Percha Creek - Macy Mine - Petroglyph Mine - Virginia Lode

LAKE VALLEY DISTRICT:  Sierra Grande Mine & Carolina Mine

CHLORIDE DISTRICT:  Black Hawk Mine

CUCHILLO NEGRO DISTRICT: Confidence Mine - Dictator Mine

HERMOSA DISTRICT: Wolford Mine

MACHO DISTRICT: Anniversary Shaft - Old Dude Shaft