Woodruffite (original) (raw)

A valid IMA mineral species - grandfathered

About WoodruffiteHide

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Formula:

Zn2+x/2(Mn4+1-xMn3+x)O2 · yH2O

Colour:

Dark brown to black

Crystal System:

Monoclinic

Name:

Named in 1953 by Clifford Frondel in honour of Samuel Woodruff (1813, New Jersey, USA - 1880+ Sparta, New Jersey, USA), an early nineteenth century zinc miner and an indefatigable mineral collector of Sparta (Ogdensburg), New Jersey, USA. Frederick A. Canfield, Jr. suggested that more Franklin minerals were collected by Woodruff than by both miners of the Losey family and by the several miners of the Kemble family. The senior Canfield purchased Samuel Woodruff's mineral collection in 1865. A Samuel Woodruff had a limestone quarry known for its chondrodite in Sparta (Ogdensburg), New Jersey, USA, and he apparently received a patent for a seed planting hoe in 1858. A notice read: "July 10, 1878 The studio of Mr. Samuel Woodruff at Sparta is well worth a visit by those who have a love for the charms in nature and art. Mr. Woodruff is best known as a painter of portraits, but excels as a delineator of fish and game. His studio is lined with the products of his skilful brush, many of which are worthy a place beside works of greater pretensions. Mr. W. is also noted as a mineralogist, and is the possessor of the finest collection of minerals, both native and foreign, to be found in the county. His cabinet contains many hundred specimens from all parts of the country, including some rare and curious specimens from Franklin Furnace and Ogdensbur[g]."

At the type locality, found chiefly as masses and crusts with a botryoidal surface and a concentric, coarsely layered internal structure. The material is very fine-grained and is opaque in crushed grains. Occasionally, corroded crystals of franklinite are found embedded in the masses, and certain of the layers, usually the outermost, may contain disseminated, platy crystals of chalcophanite.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:4312:6

02658c21-69c9-4b00-a383-2118bcc93ae8

IMA Classification of WoodruffiteHide

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Approved, 'Grandfathered' (first described prior to 1959)

IMA Formula:

Zn2(Mn4+,Mn3+)5O10 · 4H2O

Classification of WoodruffiteHide

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4.FL.25

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
L : Hydroxides with H2O +- (OH); sheets of edge-sharing octahedra

7.8.1.2

7 : MULTIPLE OXIDES
8 : AB3X7

7.5.9

7 : Oxides and Hydroxides
5 : Oxides of Zn, Cd and Hg

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of WoodruffiteHide

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Colour:

Dark brown to black

Comment:

Aggregates may be soft or powdery

Fracture:

Conchoidal, Sub-Conchoidal

Density:

4.01 g/cm3 (Measured) 3.983 g/cm3 (Calculated)

Chemistry of WoodruffiteHide

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Mindat Formula:

Zn2+x/2(Mn4+1-xMn3+x)O2 · yH2O

x ~ 0.4 and y ~ 0.7

Crystallography of WoodruffiteHide

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Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 24.81 Å, b = 2.85 Å, c = 9.58 Å
β = 93.85°

Ratio:

a:b:c = 8.705 : 1 : 3.361

Comment:

Pseudo-tetragonal (primitive); a ~8.42, c ~9.28 A.

Crystal StructureHide

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ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0003182	Woodruffite	Post J E, Heaney P J, Cahill C L, Finger L W (2003) Woodruffite: A new Mn oxide structure with 3x4 tunnels American Mineralogist 88 1697-1702		2003	0	100

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

ICDD 16-338. X-ray patterns may superficially resemble todorokite or cryptomelane. Above d values for Sandur, India. The d values of type material vary from that of Sandur: 9.51 (50), 6.99 (40), 4.77 (100), 4.40 (30), 3.48 (20), 3.13 (20), 2.63 (20), 2.466 (40), 2.404 (50), 2.225 (50), 2.131 (20), 1.984 (30), 1.985 (20), 1.747 (20), 1.660 (20), 1.423 (50) (Frondel, 1953). See also x-ray data of Meisser and Perseil (1993) showing better data fit with type material.

Geological EnvironmentHide

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Type Occurrence of WoodruffiteHide

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General Appearance of Type Material:

Botryoidal with fine-grained internal structure may show concentric layers.

Geological Setting of Type Material:

Deeply weathered manganese-zinc minerals from a zinc silicate and zinc oxide deposit hosted by marble.

Associated Minerals at Type Locality:

Other Language Names for WoodruffiteHide

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Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Fluorescence of WoodruffiteHide

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Not fluorescent in ultraviolet

Other InformationHide

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Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for WoodruffiteHide

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References for WoodruffiteHide

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Reference List:

Meisser, Nicolas & Perseil, Elena Adriana (1993): Occurrence of woodruffite, (Zn,Mn+2)Mn3+4O7.1-2H2O, hetaerolite, ZnMn2O4, and hydrohetaerolite, HZnMn2-xO4, of supergene origin in a skarn of Mount Chemin (Valais, Switzerland). Schweizerische Mineralogische und Petrographische Mitteilungen, 73, 11-19.

Localities for WoodruffiteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.