Leucophoenicite
Current inventory: 0 gems
 

  
Leucophoenicite was named in 1899 by Samuel Lewis Penfield and Charles Hyde Warren from the Greek words λευκοσ (leukos) meaning pale and Фοινιζ (foinis) meaning purplish red in allusion to its common color.

Discovered in 1897; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Mn²⁺₇(SiO₄)₃(OH)₂

Manganese Silicate Hydroxide

Molecular Weight:

694.83 gm

Composition:

Manganese

55.35 %

Mn

71.47 %

MnO

Silicon

12.13 %

Si

25.94 %

SiO₂

Hydrogen

0.29 %

H

2.59 %

H₂O

Oxygen

32.24 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/B.04-90

Nickel-Strunz 10th Ed. ID:

9.AF.60

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination

Related to:

Humite Group. Dimorph of Manganhumite.

Members of Group:

Humite Group: Chondrodite, Clinohumite, Humite, Hydroxylchondrodite, Hydroxylclinohumite, Norbergite 

Varieties:

None

Synonyms:

ICSD 15176, PDF 22-1168

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals rare, typically slender, prismatic, elongated and striated || [010], to 8 mm; in isolated grains or granular massive.

Twinning:

On {001}, common, contact or interpenetrant twins, lamellar. 

Physical Properties

Cleavage:

Imperfect on {001}

Fracture:

Irregular/uneven

Tenacity:

Brittle

Moh's Hardness:

5.5 - 6.0

Density:

3.848 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Brown to light purple-red, raspberry-red, deep pink to light pink; rose-red to colorless in thin section

Transparency:

Transparent to translucent

Luster:

Vitreous

Refractive Index:

1.751 - 1.782  Biaxial ( - )

Birefringence:

0.031

Dispersion:

Slight; r > v

Pleochroism:

Faint; rose-red parallel to {001}; colorless perpendicular to {001}

Occurances

Geological Setting:

A late-stage hydrothermal or contact zone mineral in veins and skarns in a metamorphosed stratiform Zn-Mn orebody (Franklin, New Jersey, USA).

Common Associations:

Willemite, Franklinite, Calcite, Vesuvianite, Garnet, Sussexite, Rhodochrosite, Pyrochroite, Tephroite, Sonolite, Jerrygibbsite, Glaucochroite, Manganosite, Copper, Zincite (Franklin, New Jersey, USA); Barysilite, Spessartine, Vesuvianite, Barite, Copper, Hausmannite (Kombat mine, Namibia).

Common Impurities:

Fe, Mg, Zn, Ca, Na, K, H₂O

Co-Type Localities:

• Franklin Mine, Franklin, Franklin Mining District, Sussex County, New Jersey, USA
• Buckwheat pit (Southwest opening; Buckwheat Mine), Franklin Mine, Franklin, Franklin Mining District, Sussex County, New Jersey, USA

Year Discovered:

1897 (identified as a new mineral species in 1899)

View mineral photos:

Leucophoenicite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Leucophoenicite is a rare silicate mineral that belongs to the Humite Group of minerals that also includes Chondrodite, Clinohumite, Humite and Norbergite among others. Leucophoenicite is typically found as translucent light purple-red, raspberry-red or deep pink, granular massive material as crystals are rare. It has a vitreous luster and Moh's hardness of 5.5-6. Leucophoenicite is often associated with Willemite as seen in the gem pictured above. The top half of the gem is purple-red Leucophoenicite and the bottom half is transparent greenish-yellow Willemite. Leucophoenicite is not fluorescent but the Willemite fluoresces bright green under both SW UV and LW UV.

Leucophoenicite was discovered by J. J. McGovern (?-1915) at the Franklin Mine in New Jersey. For many years McGovern was in charge of the picking table at the head of the mine shaft and was one of the foremost collectors of Franklin minerals and added much to the knowledge of Franklin mineralogy. The mineral McGovernite was named in his honor in 1927 by American mineralogist and crystallographer Charles Palache (1869-1954) and chemist Lawson Henry Bauer (1888-1954). The specimen McGovern found at the Franklin Mine was given to American geologist Charles Hyde Warren (1876-1950) in 1897. It was first thought to be Clinohedrite deeply colored by manganese, but was identified as a new mineral species by Warren and Samuel Lewis Penfield (1856-1906) in 1899. The crystallography of Leucophoenicite was first described by Charles Palache in 1910, as Penfield and Warren were unable to determine the crystal system. Leucophoenicite was named in 1899 by Warren and Penfield from the Greek words λευκοσ (leukos) meaning pale and Фοινιζ (foinis) meaning purplish red in allusion to its common color.

Leucophoenicite distribution: at Franklin, Sussex County, New Jersey, USA. From Pajsberg, Värmland, Sweden. In the Valsesia-Valtournanche area, Val d'Aosta, Italy. In the Kombat mine, 49 km south of Tsumeb, Namibia. From Hotazel, near Kuruman, Cape Province, South Africa.
 

  
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