Ganophyllite
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Ganophyllite was named in 1890 by Axel Hamberg from the Greek words ganos meaning luster and phyll meaning leaf, in allusion to the high luster on cleavage surfaces.

Discovered in 1890; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

(K,Na,Ca)₂Mn₈(Si,Al)₁₂(O,OH)₃₂ • 8H₂O

Hydrated Potassium Sodium Calcium Manganese Silicate Hydroxide

Molecular Weight:

1,514.20 gm

Composition:

Potassium

3.87 %

K

4.67 %

K₂O

Sodium

0.76 %

Na

1.02 %

Na₂O

Magnesium

2.41 %

Mg

3.99 %

MgO

Manganese

21.77 %

Mn

28.11 %

MnO

Aluminum

5.88 %

Al

11.11 %

Al₂O₃

Silicon

16.69 %

Si

35.71 %

SiO₂

Hydrogen

1.60 %

H

14.28 %

H₂O

Oxygen

47.02 %

O

100.00 %

98.89 %

= TOTAL OXIDE

Classification

Mineral Classification:

SILICATES (Germanates)

Strunz 8th Ed. ID:

8/H.17-60

Nickel-Strunz 10th Ed. ID:

9.EG.30

9 : SILICATES (Germanates)
E : Phyllosilicates
G : Double nets with 6-membered and larger rings

Related to:

Ganophyllite Group. The potassium analogue of Eggletonite.

Members of Group:

Ganophyllite Group: Eggltonite, Ganophyllite, Tamaite

Varieties:

None

Synonyms:

ICSD 64788, PDF 21-359

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Short to long prismatic crystals, to 2.5 cm, forming balls or rosettes; as six-sided micaceous flakes or fine-grained micaceous aggregates

Twinning:

None

Physical Properties

Cleavage:

Perfect micaceous on {001}; distinct on {100}, {010}

Fracture:

Foliated

Tenacity:

Brittle

Moh's Hardness:

4.0 - 4.5

Density:

2.77 - 2.84 (g/cm³)

Luminescence:

None

Radioactivity:

Barely Detectable; GRapi = 55.45 (Gamma Ray American Petroleum Institute Units)

Optical Properties

Color:

Light brown, brownish yellow, cinnamon brown, pale pink

Transparency:

Transparent to translucent

Luster:

Brilliant on cleavage surfaces

Refractive Index:

1.537 - 1.613  Biaxial ( - )

Birefringence:

0.076

Dispersion:

Weak; r < v

Pleochroism:

Dark to pale yellow-brown

Occurances

Geological Setting:

In manganese-rich portions of metamorphosed Zn-Mn mineral deposits.

Common Associations:

Calcite, Rhodonite, Caryopilite, Barite, Lead, Garnet, Manganoan Biotite, Pyrophanite (Harstigen mine, Sweden); Rhodonite, Willemite, Bustamite, Axinite, Clinohedrite, Datolite, Roeblingite, Charlesite (Franklin, New Jersey, USA); Parsettensite, Caryopilite (Molinello mine, Italy).

Common Impurities:

Fe, Zn, Pb, Ca, Ba

Type Locality:

Harstigen Mine, Pajsberg, Persberg district, Filipstad, Värmland, Sweden

Year Discovered:

1890

View mineral photos:

Ganophyllite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Ganophyllite was named in 1890 by Axel Hamberg from the Greek words ganos mening luster and phyll meaning leaf, in allusion to the high luster on cleavage surfaces. Ganophyllite is a somewhat rare Silicate mineral that commonly forms as cinnamon brown to pale pink prismatic crystals, to 2.5 cm forming balls or rosettes or as six-sided micaceous flakes. 

Locations for Ganophyllite: In Sweden, from the Harstigen mine, near Persberg, and at Långban, Väarmland; and in the Sjö mine, near Grythyttan, Örebro. At the Benallt and Nant mines, Rhiw, Lleyn Peninsula, Wales. From the Molinello and Gambatesa manganese mines, near Chiavari, Val Graveglia, Liguria, Italy. In the USA, in the Maple-Hovey deposits, west of Bridgewater, Aroostook County, Maine, and at Franklin, Sussex County, New Jersey. From Mont Saint-Hilaire, Quebec, Canada. In the Ananai mine, Nagaoka, Kochi Prefecture; the Noda-Tamagawa mine, Iwate Prefecture; the Kumahata mine, Shiga Prefecture; and the Osu and Yonoyama mines, Kita, Ehime Prefecture, Japan. From Broken Hill, New South Wales, Australia.
 

  
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