Vanadinite

Vanadinite PB5(VO4)Cl
 Hillsboro Mining District, Sierra County, NM
Specimen at the Mineral Museum New Mexico Institute of Mining and Technology Socorro, New Mexico
Photograph taken on April 6, 2016

Most people like nice pure samples, with rock that is problematic for three reasons: 1) minerals and rocks are often in a matrix; 2) the particular sample of interest is often mixed in with other minerals (a bit different from the matrix issue); and 3) because these are chemical creatures there may be various impurities (or variations) in the chemical composition of the specimen.  I deal with “clines” all the time in studying avian speciation but had never really thought about it from a “rock and mineral” perspective until now.  

Vanadinite is in the Apatite group of minerals which includes the mineral Mimetite.  An intermediate mineral type between Vanadinite and Mimetite is Vanadinite var. Endlichite (which is shown below).  Vanadinite contains the vanadate radical is VO4, when it is replaced with an arsenate radical (AsO4) the mineral is Mimetite.  Endlichite, Pb5([V,As]O4)3Cl, is often considered to be an arsenic-rich form of Vanadinite.  To make things worse, if the chemical composition is composed of a phosphate radical Pb5(PO4)3Cl, the mineral is pyromorphite.

The Vanadinite var. Endlichite specimen shown below is labeled as being from the Sierra Grande Mine in the Hillsboro Mining District of Sierra County, New Mexico.  The Sierra Grande Mine is actually in the Lake Valley Mining District of Sierra County.  I assume that the labeling simply got the District wrong (note, however, that names of Districts seem to morph over time and with reference).

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

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

GEORGETOWN DISTRICT: Mimbres Mine - Redbird Prospect

LAKE VALLEY DISTRICT:  Sierra Bella Group (Bella Chute & Sierra Grande Mine)

CUCHILLO NEGRO DISTRICT: Confidence Mine - Dictator Mine

HERMOSA DISTRICT: Wolford Mine

MACHO DISTRICT: Anniversary Shaft - Old Dude Shaft

COOKE’S PEAK DISTRICT: Jose District - Faywood Mine

OLD HADLEY MINING DISTRICT: Copper Mine - Rock Island Mine

Vanadinite, PB5(VO4)Cl
From the Petroglyph Mine, Hillsboro Mining District, Sierra County, NM
Specimen at the Mineral Museum, New Mexico Institute of Mining and Technology, Socorro, NM
Photograph taken on April 6, 2016

Vanadinite (var. Endlichite)    PB5(VO4)3Cl
From  Sierra Grande Mine,  Lake Valley Mining District Sierra County, NM
 Mineral Museum New Mexico Institute of Mining and Technology Socorro, New Mexico
Photograph taken on April 6, 2016

Vanadinite var. Endlichite PB5(VO4)3Cl
From the Macy (Vanadinite) Mine, Hillsboro Mining District, NM.
Specimen at Mineral Museum, NM Institute of Mining and Technology, Socorro, NM
Photograph taken on April 6, 2016


© Robert Barnes 2017