Leadhillite
Current inventory:  0 gems
 

  
Leadhillite was named in 1832 after the Type Locality, Susanna mine, Leadhills, Lanarkshire, Scotland.

Discovered in 1832; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Pb₄(SO₄)(SO₃)₂(OH)₂

Lead Sulfate Carbonate Hydroxide

Molecular Weight:

1,078.90 gm

Composition:

Hydrogen

0.19 %

H

1.67 %

H₂O

Lead

78.82 %

Pb

88.68 %

PbO₂

Carbon

2.23 %

C

8.16 %

CO₂

Sulfur

2.97 %

S

7.42 %

SO₃

Oxygen

17.80 %

O

100.00 %

105.93 %

= TOTAL OXIDE

Classification

Mineral Classification:

Carbonates (Nitrates)

Strunz 8th Ed. ID:

6/B.13-50

Nickel-Strunz 10th Ed. ID:

5.BF.40

5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H₂O
F : With (Cl), SO₄, PO₄, TeO₃

Related to:

Trimorphous with: Macphersonite and Susannite. The monoclinic dimorph of Susannite.

Varieties:

None

Synonyms:

Lead sulphato-tricarbonate, Maxite, ICSD 64807, PDF 35-617

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals, to 13 cm, are usually thin to thick tabular pseudohexagonal, with hexagonal outline; several rhombohedral and pyramidal forms common; may be barrel-shaped, or pseudorhombohedral {101} and {142}, also prismatic parallel to [001], or equant, granular or massive. When [101] is developed the faces may show striations, or be curved. Over 40 forms noted; granular, massive.

Twinning:

On {140}, {340}, {140}, very common, giving pseudohexagonal groupings. 

Physical Properties

Cleavage:

Perfect on {001} and easy. Parting: translation gliding on {001}, as well as twin gliding with K1(340), σ2[140]; K2(34¯0), σ1[140].

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

2.5 - 3.0

Density:

6.55 (g/cm³)

Luminescence:

Pale yellowish under Short Wave UV

Radioactivity:

Not Radioactive

Thermal Behaviour:

Heating results in a reversible transformation into Susannite. 2E is approximately 20° (2V ~ 10°) at ambient temperature (for Na) and decreases with increasing temperature. It becomes uniaxial negative at about 125° and remains so at higher temperatures.

Other:

Soluble in nitric acid with effervescence, rendering a residue of lead sulphate. Exfoliates in hot water.

Health Warning:

Caution: Contains lead - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest.

Optical Properties

Color:

Colorless, white, gray, pale yellow, yellow, yellowish green, pale green, pale bluish green, pale blue, brown; colorless in transmitted light

Transparency:

Transparent to translucent

Luster:

Resinous to adamantine, pearly on {001}

Refractive Index:

1.870 - 2.010  Biaxial ( - )

Birefringence:

0.140

Dispersion:

Strong; r < v

Pleochroism:

n/a

Occurances

Geological Setting:

An uncommon secondary mineral in the oxidation zone of lead deposits.

Common Associations:

Cerussite, Anglesite, Lanarkite, Caledonite, Linarite (Leadhills, Scotland);
Cerussite, Caledonite, Linarite, Diaboleite, Boleite, Wherryite, Paralaurionite, Brochantite (Mammoth-St. Anthony mine, Arizona, USA).

Common Impurities:

n/a

Type Locality:

Susanna Mine (Glennery Scar Vein; Susanna Vein [Scar Vein]; Portobello Vein; Humby Vein; Lead Vein), Leadhills, South Lanarkshire, Strathclyde (Lanarkshire), Scotland, UK

Year Discovered:

1832

View mineral photos:

Leadhillite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Leadhillite is a lead sulfate carbonate closely related to and trimorphous with Susannite and Macphersonite. Trimorphs are three different minerals that share the same chemistry, but have different crystal structures. In this case, Leadhillite is monoclinic, Susannite is trigonal and Macphersonite is orthorhombic. Leadhillite is most often found as small to microscopic clear to white tabular pseudohexagonal crystals but can also be found in larger sizes, to 13 cm, as prismatic crystals and in various shades of yellow, green, blue and brown. Leadhillite is quite soft with a Mohs hardness of only 2.5 but a relatively high specific gravity of 6.26 to 6.55 and resinous to adamantine luster. Leadhillite was named in 1832 after the type locality, Susanna mine, Leadhills, Lanarkshire, Scotland. Some of the best specimens have come from the Mammoth Mine, Tiger, Arizona. Attractive specimens are not rare but certainly not common but faceted gems are very rare.

Distribution: In Scotland, from Leadhills, Lanarkshire, and Wanlockhead, Dumfriesshire; in the Drumruck mine, Kirkcudbrightshire. In England, from Caldbeck Fells, Cumbria; at Penberthy Croft, St. Hilary, and in the Greystone quarry, Levant, Cornwall. From Bleiberg, Carinthia, Austria. In the USA, from the Beer Cellar mine, Granby, Newton County, Missouri; in the Tintic district, Juab County, Utah; in Arizona, fine crystals from the Mammoth-St. Anthony mine, Tiger, Pinal County, in the Rowley mine, near Theba, Maricopa County, at the Grand Reef mine, Gila County, and from Bisbee, Cochise County. In California, at the Blue Bell claims, near Baker, San Bernardino County; from the Searchlight district, Clark County, and in the Chalk Mountain mine, Chalk Mountain district, Churchill County, Nevada; from Leadville, Lake County, Colorado. Very large crystals from Tsumeb, Namibia. At Dundas, Tasmania, Australia. A few other localities are known.
 

  
Leadhillite gems for sale:

We have not photographed our Leadhillite gems yet. Please check back soon.