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Fornacite

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Formula:
Pb
 
2
Cu(CrO
 
4
)(AsO
 
4
)(OH)
System:MonoclinicColour:Deep olive-green; golden ...
Hardness:2 - 3
Name:
Named in 1916 by Antoine François Alfred Lacroix from the Latin fornax "the furnace" in honor of geographer and French colonial governor of Middle Congo (1911-16), Lucien Louis Fourneau [February 16, 1867, Saint-Cyr-l'Ecole, Yvelines, France - August 3, 1930, Perros-Guirec, Côtes-du-Nord [now Côtes-d'Armor], France], whose name also translates to "the furnace".
Fourneau was lieutenant governor of Oubangui-Chari (1909-10) and commissioner of French Cameroons (1916-19).
Isostructural with:Molybdofornacite, Vauquelinite


Fornacite-Vauquelinite Series. The arsenate analogue of vauquelinite.

Related to the Brackebuschite Group.

Classification of Fornacite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:6/F.02-20
Nickel-Strunz 10th (pending) edition ID:7.FC.10

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
F : Chromates
C : With PO4, AsO4, SiO4
Dana 8th edition ID:43.4.3.2

43 : COMPOUND PHOSPHATES, ETC.
4 : Anhydrous Compound Phosphates, etc·, Containing Hydroxyl or Halogen
Hey's CIM Ref.:22.5.4

22 : Phosphates, Arsenates or Vanadates with other Anions
5 : Phosphates, arsenates or vanadates with chromate, molybdate, niobate or tantalate
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Type Occurrence of Fornacite

Type Locality:Renéville Mine (Djoué Mines), Renéville, Kindanba District, Pool Department, Republic of Congo (Brazzaville)
General Appearance of Type Material:Confused groups of small, prismatic crystals.
Year of Discovery:1915
Associated Minerals at type locality:
Dioptase

Occurrences of Fornacite

Geological Setting:Oxidized zones of polymetallic deposits

Physical Properties of Fornacite

Lustre:Resinous, Waxy, Greasy
Diaphaneity (Transparency):Transparent
Colour:Deep olive-green; golden yellow in transmitted light (small grains).
Streak:Olive green
Hardness (Mohs):2 - 3
Tenacity:Brittle
Fracture:Irregular/Uneven, Conchoidal, Sub-Conchoidal
Density (measured):6.27 g/cm3
Density (calculated):6.30 g/cm3

Crystallography of Fornacite

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:P21/b {P1 1 21/b} {P21/c} {P1 21/c 1} {P21/a}
Space Group Setting:P1 21/c 1
Cell Parameters:a = 8.101(2) Å, b = 5.893(11) Å, c = 17.547(9) Å
β = 110.00(4)°
Ratio:a:b:c = 1.375 : 1 : 2.978
Unit Cell Volume:V 787.16 ų (Calculated from Unit Cell)
Z:4
Morphology:Short bladed crystals in divergent groupings.
Comment:Other cell given: 7.91, 5.91, 17.46 A, xxx°.
X-Ray Powder Diffraction:
d-spacingIntensity
8.22 (50)
4.80 (90)
3.31 (100)
2.98 (100)
2.88 (100)
2.80 (100)
2.71 (90)

Optical Data of Fornacite

Type:Biaxial (+)
RI values: nα = 2.142 nγ = 2.242
Birefringence:0.100
Maximum Birefringence:δ = 0.100

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:Strong
Pleochroism:Non-pleochroic
Comments:2V rather large.

Chemical Properties of Fornacite

Formula:
Pb
 
2
Cu(CrO
 
4
)(AsO
 
4
)(OH)
Simplified for copy/paste:Pb2Cu(CrO4)(AsO4)(OH)
Essential elements:As, Cr, Cu, H, O, Pb
All elements listed in formula:As, Cr, Cu, H, O, Pb

Relationship of Fornacite to other Species

Series:Forms a series with Vauquelinite (see here)
Common Associates:
WulfeniteMimetiteHemimorphiteFluoriteDioptase
Chrysocolla
Related Minerals - Nickel-Strunz Grouping):

- +
7.FC.05Vauquelinite
Pb
 
2
Cu(CrO
 
4
)(PO
 
4
)(OH)
7.FC.10Molybdofornacite
Pb
 
2
Cu(MoO
 
4
,CrO
 
4
)(AsO
 
4
,PO
 
4
)(OH)
7.FC.15Hemihedrite
Pb
 
10
Zn(CrO
 
4
)
 
6
(SiO
 
4
)
 
2
(F,OH)
 
2
7.FC.15Iranite
Pb
 
10
Cu(CrO
 
4
)
 
6
(SiO
 
4
)
 
2
(F,OH)
 
2
7.FC.20Cassedanneite
Pb
 
5
(CrO
 
4
)
 
2
(VO
 
4
)
 
2
· H
 
2
O
7.FC.20Embreyite
Pb
 
5
(CrO
 
4
)
 
2
(PO
 
4
)
 
2
· H
 
2
O
Related Minerals - Hey's Index Grouping:

- +
22.5.1Vauquelinite
Pb
 
2
Cu(CrO
 
4
)(PO
 
4
)(OH)
22.5.2Embreyite
Pb
 
5
(CrO
 
4
)
 
2
(PO
 
4
)
 
2
· H
 
2
O
22.5.3Cassedanneite
Pb
 
5
(CrO
 
4
)
 
2
(VO
 
4
)
 
2
· H
 
2
O
22.5.5Molybdofornacite
Pb
 
2
Cu(MoO
 
4
,CrO
 
4
)(AsO
 
4
,PO
 
4
)(OH)
22.5.6Mendozavilite-NaFe
[Na
 
2
(H
 
2
O)
 
15
Fe
3+
 
(H
 
2
O)
 
6
][Mo
 
8
P
 
2
Fe
3+
3
O
 
35
(OH)
 
2
]
22.5.7Paramendozavilite
[KAl
 
4
(H
 
2
O)
 
30
][Mo
 
12
P
 
6
Fe
3+
6
O
 
60
(OH)
 
13
]
22.5.8Betpakdalite-CaCa
[Ca
 
2
(H
 
2
O)
 
17
Ca(H
 
2
O)
 
6
][Mo
6+
8
As
5+
2
Fe
3+
3
O
 
36
(OH)]
22.5.9Betpakdalite-NaCa
[Na
 
2
(H
 
2
O)
 
17
Ca(H
 
2
O)
 
6
][Mo
6+
8
As
5+
2
Fe
3+
3
O
 
34
(OH)
 
3
]
22.5.10Obradovicite-KCu
[K
 
2
(H
 
2
O)
 
17
Cu(H
 
2
O)
 
6
][Mo
 
8
As
 
2
Fe
3+
3
O
 
34
(OH)
 
3
]
22.5.11Melkovite
[Ca
 
2
(H
 
2
O)
 
15
Ca(H
 
2
O)
 
6
][Mo
 
8
P
 
2
Fe
3+
3
O
 
36
(OH)]
22.5.12Rankachite
Ca
 
0.5
(V
4+
 
,V
5+
 
)(W
6+
 
,Fe
3+
 
)
 
2
O
 
8
(OH) · 2H
 
2
O
22.5.13Olmsteadite
KFe
2+
2
(Nb
5+
 
,Ta
5+
 
)(PO
 
4
)
 
2
O
 
2
· 2H
 
2
O
22.5.14Johnwalkite
K(Mn
2+
 
,Fe
2+
 
,Fe
3+
 
)
 
2
(Nb
5+
 
,Ta
5+
 
)(PO
 
4
)
 
2
O
 
2
· 2(H
 
2
O,OH)

Other Names for Fornacite

Synonyms:
Furnacite
Other Languages:
Dutch:Fornaciet
German:Fornacit
Furnacit
Italian:Fornacite
Russian:Форнасит
Spanish:Fornacita
Furnacita

Other Information

Fluorescence in UV light:Not Fluorescent in UV.
Other Information:Totally soluble in HCl.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Fornacite

Reference List:

- +
Lacroix (1915) Bulletin de la Société française de Minéralogie: 38: 198.

Lacroix (1916) Bulletin de la Société française de Minéralogie: 39: 84.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 652.

Bariand, P. and Herpin, P. (1962): Nouvelles données sur la fornacite (chromo-arseniate de plomb et de cuivre). Bull. Soc. Franc. Minéral., 85, 309-311. (in French).

American Mineralogist: 49: 447.

Zeitschrift für Kristallographie: 124: 385-397.

Internet Links for Fornacite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Fornacite details from Handbook of Mineralogy (PDF)
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  • Localities for Fornacite

    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Australia
     
    • New South Wales
      • Yancowinna Co.
        • Broken Hill
    Australian Min. 3:1 (1997)
    • Western Australia
      • Leonora Shire
        • Ten Mile Outcamp
    Nickel, E.H. (1982) Secondary minerals from the oxidized zone of the Teutonic Bore sulphide deposit. The Australian Mineralogist, No. 40, December 1982, pg. 219-223.
      • Roebourne Shire
        • Whim Creek
    No reference listed
    Chile
     
    • Atacama Region
      • Copiapó Province
        • Cachiyuyo de Llampos district
    Maurizio Dini & Robert Jenkins collections; material analysed by Mr. Jenkins
    Germany
     
    • Hesse
      • Odenwald
        • Lautertal (Odenwald)
          • Reichenbach
            • Hohenstein
    Lapis, 12 (10), 23-32+58.
      • Spessart
        • Freigericht
          • Altenmittlau
    • Saxony
      • Glauchau
        • Callenberg
    Lapis, 16 (9), 13-26.
    Greece
     
    • Attikí Prefecture (Attica; Attika)
      • Lavrion District (Laurion; Laurium)
        • Lavrion District Mines
          • Agios Konstantinos [St Constantine] (Kamariza)
            • Kamariza Mines (Kamareza Mines)
              • Hilarion area
    Fritz Schrieber
          • Sounion Area
            • Agia Varvara Mines (St Barbara Mines)
    Schnorrer, G. & Breitenbach, H. (1996): Lavrion: Neufunde aus dem antiken Bergbau und in historischen Schlacken. Lapis, 21 (1), 45-48; 62.; Lapis, 24, 7/8, (1999)
    Hanke, H. (1998): Laurion - ein Rückblick auf die Funde der letzten drei Jahre. Mineralien-Welt, 9 (2), 37-45.
    Wendel, W. & Markl, G. (1996): Eine Antimonit-Paragenese und weitere Neufunde aus Lavrion. Lapis, 21 (11), 40-42; 62.; Branko Rieck Collection
    Lapis, 24, 7/8 (1999)
    Hungary
     
    • Fejér Co.
      • Szár Hill
        • Szabadbattyán
    Szakáll: Minerals of Szár Hill, 2004
    Iran
     
    • Esfahan Province (Isfahan Province; Aspadana Province)
      • Nain County (Nayin County)
        • Anarak District
    P. Bariand and P. Herpin, Bull. Soc. Franç. Minér. Crist. , 1963, LXXXVI, pp. 133-135.
    • Yazd Province
      • Nayband (Neyband)
    Bariand, P. & Poullen, J.F. (1980): Rare Chromates from Seh-Changi, Iran. Mineralogical Record 11, 293-297
    Italy
     
    • Piedmont
      • Torino Province
        • Canavese District
          • Chiusella Valley
            • Traversella
    SEM/EDS 18/09/2001 MNHN-Paris
    Mexico
     
    • Sonora
      • Mun. de Moctezuma
        • Moctezuma
    Lapis 2001(1), 11-40
    Morocco
     
    • Souss-Massa-Draâ Region
      • Ouarzazate Province
        • Tazenakht
          • Bou Azer District (Bou Azzer District)
            • Oumlil
    Favreau, G. and Dietrich, J. E. (2006). Die Mineralien von Bou Azzer. Lapis 31(7/8), 27-68
    Namibia
     
    • Erongo Region
      • Swakopmund District
        • Namib-Naukluft National Park
    Bezing, L. von, Bode, R. & Jahn, S. (2008): Namibia Minerals and Localities. Edition Schloss Freudenstein, Bode Verlag GmbH, Haltern, 338 pp. (in English)
    • Otjikoto Region (Oshikoto)
      • Tsumeb
    Min. Record (in press)
    Republic of Congo (Brazzaville)
    Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 652.
    • Pool Department
      • Kindanba District
        • Renéville
    Lacroix (1915) Bulletin de la Société française de Minéralogie: 38: 198.
    Russia
     
    • Urals Region
      • Middle Urals
        • Sverdlovskaya Oblast'
          • Ekaterinburg (Sverdlovsk)
            • Berezovskii (Berezovskii Zavod)
    Клейменов Д.А., Ерохин Ю. В., Прибавкин С.В. Форнасит из зоны окисления Березовского золоторудного месторождения. // Уральская летняя минералогическая школа-97, 1997, с.96-98.; Pavel M. Kartashov analytical data (2011)
                • Uspenskaya Mt
    Pavel M. Kartashov analytical data (2012)
    South Africa
     
    • Mpumalanga Province
    Minerals of South Africa
    • North West Province
      • Olifantspoort
    Reeks, G. (2007) Olifantspoort Mine, Olifantspoort, Northern Province. South African Micromount Society newsletter: 33(3)
    UK
     
    • England
      • Somerset
        • Cranmore
    Turner, R.W. and Rumsey, M.S. (2010): Mineral Relationships in the Mendip Hills. Journal of the Russell Society, vol 13, pp 3-46; Turner, R. (2006): A mechanism for the formation of the mineralized Mn deposits at Merehead Quarry, Cranmore, Somerset, England. Mineralogical Magazine 70, 629-653; Turner R.W. and Rumsey, M.S. (2007) Merehead Mineralogy - an Update. Russell Soc Newsletter, No 50, pp 17-18 (March 2007); UK Journal of Mines and Minerals (2006), no. 27, pp 6-7.
    USA
     
    • Arizona
      • Cochise Co.
        • Dragoon Mts
          • Johnny Lyon Hills
            • Tres Alamos Wash
    Robert Jenkins Raman Spectroscopy
        • Mule Mts
          • Warren District
            • Bisbee
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225; Graeme, R. (1981), Famous mineral localities: Bisbee, AZ, Min.Rec.: 12: 256-319.
        • Tombstone Hills
          • Tombstone District
    Rob Bowell, lab tested
      • Gila Co.
        • Dripping Spring Mts
          • Banner District
            • Hayden area
              • Chilito
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
        • Payson District (Green Valley District)
          • Oxbow Estates area
            • Lousy Gulch
    Williams, S. A. (1981): Duhamelite, Cu4Pb2Bi(VO4)4(OH)3.8H2O, a new Arizona mineral. Mineralogical Magazine 44, 151-152.
      • La Paz Co.
        • Granite Wash Mts
          • Ellsworth District
    Mineral collected by Jerry A. Baird
        • New Water Mts
          • New Water District
            • Moore Mine group
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
        • Trigo Mts
          • Silver District
    XRD analysis by Dr. Anthony Kampf.
      • Maricopa Co.
        • Big Horn Mts
          • Osborn District
            • Tonopah
              • Belmont Mountain
                • Tiger Wash
    Ron Layton
        • Painted Rock Mts
          • Painted Rock District
            • Theba
    EDS analysis Association Jean WYART, Paris - specimen Georges FAVREAU
      • Pima Co.
        • Ajo District
          • Little Ajo Mts
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
        • Empire Mts
          • Empire District
            • Hilton (Lead Mountain)
              • Copper Camp
                • Hilton Mines (Hilton Mine group; Hiltano group; Hiltano & State of Maine group)
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
        • Tucson Mts
          • Amole District
            • Jaynes
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
            • Saguaro National Monument
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225; Bideaux, R.A., et al (1960), Some new occurrences of minerals of AZ, AZ Geol. Soc. Digest: 3: 53-56; Jones, D. (1983), The Old Yuma mine, Min.Rec.: 14: 95-107.
      • Pinal Co.
        • Mammoth District
          • Tiger
            • St. Anthony deposit
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225; Bideaux, R.A., et al (1960), Some new occurrences of minerals of Arizona, AZ Geol. Soc. Digest: 3: 53-56; Bideaux, R.A. (1980), Tiger, AZ, Min.Rec.: 11: 155-181;
        • Tohono O'odham Indian Reservation
          • Silver Reef District
            • Tat Momoli Mts
              • Chuichu area
                • Silver Reef Mountains area
                  • White Horse Pass area
    Collected by and in the collection of Brent Thorne
          • Slate Mts
            • Casa Grande District
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225, 370.
          • Vekol Mts
            • Vekol District
              • Kohatk
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
    R. D. Green
      • Yavapai Co.
        • Black Rock District
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
        • Bradshaw Mts (Bradshaw Range)
          • Castle Creek District
    Rolf Luetcke
    • California
      • Inyo Co.
        • Inyo Mts (Inyo Range)
          • Manzanar Station area
    Adams, Paul (2010) The Brown Monster and Reward Mines Inyo County, California. Mineralogical Record 41:175-193.
    Raman ID 12-13-2007 on material personally collected by Tom Trebisky.; Adams, Paul (2010) The Brown Monster and Reward Mines Inyo County, California. Mineralogical Record 41:175-193.
        • Panamint Mts (Panamint Range)
          • Ubehebe District
            • Big Dodd Spring
    [MinRec 32:393]
      • San Bernardino Co.
        • Baker
          • Otto Mountain
    Joe Marty specimens
    Collected by and in the collection of Brent Thorne.
        • Soda Lake Mts
          • Baker
    The Blue Bell Claims San Bernardino County, California, Maynard, M., et al., pg. 44
    • Idaho
      • Clark Co.
        • Skull Canyon District
          • Kaufman
    Ream, Lanny R. 2004. Idaho Minerals, 2nd edition, Revised and Updated
    • Montana
      • Beaverhead Co.
        • Argenta District
          • Argenta
            • Stapleton Gulch
    http://www.mineralnews.com/MinNews/MN18-2.html
    • Nevada
      • Clark Co.
        • Alunite District
    Richard W. Thomssen
        • Eldorado District
    NBMG Spec. Pub. 31 Minerals of Nevada
        • Eldorado Mts
    Rolf Luetcke
        • Goodsprings District
    NBMG Spec. Pub. 31 Minerals of Nevada
    Haynes, P. E. (2007):"Minerals of the Fredrickson Mine, Goodsprings District, Clark County, Nevada". New Mexico Geology 29(4),138.
          • Goodsprings
    NBMG Spec. Pub. 31 Minerals of Nevada
    Collected by and in the collection of Brent Thorne.
    NBMG Spec. Pub. 31 Minerals of Nevada; Rocks & Minerals 83:1 pp 65-69
    Self collected by Brent Thorne
    Collected by Joe Marty.
      • Elko Co.
        • Spruce Mountain District
    NBMG Spec. Pub. 31 Minerals of Nevada
      • Esmeralda Co.
    NBMG Spec. Pub. 31 Minerals of Nevada
    NBMG Spec. Pub. 31 Minerals of Nevada
      • Humboldt Co.
        • Iron Point District
          • Valmy
    Dr. William S. Wise presentation to Northwest Micro Mineral Study Group on 1 May 2004, Update on Mineralogy of the Silver Coin Mine, Iron Point District, Edna Mountains, Humboldt Co., Nevada
      • Nye Co.
        • Belmont District
    NBMG Spec. Pub. 31 Minerals of Nevada
    • New Mexico
      • Hidalgo Co.
        • San Simon District
          • Granite Gap
    R&M 77:5 p298-305
    Northrop, Minerals of New Mexico, 3rd Rev. Ed., 1996
        • Cooks Peak District (Cooke's Peak District)
          • Old Hadley (Graphic) Mining District
    Walstrom 2006 New Mexico Mineral Symposium abstracts
    Minerals of New Mexico 3rd ed.
      • Socorro Co.
        • North Magdalena District
    Minerals of New Mexico 3rd ed.
          • Silver Hill area
    Minerals of New Mexico 3rd ed.
        • Socorro Peak District
    Northrop, Minerals of New Mexico, 3rd Rev. Ed., 1996
    • Utah
      • Juab Co.
        • East Tintic Mts
          • Tintic District
            • Mammoth
    Ron Layton
    Uzbekistan
     
    • Tashkent Viloyati (Toshkent)
      • Almalyk
    Pavel M. Kartashov data
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