Taranakite
A valid IMA mineral species - grandfathered
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About Taranakite
The Sugar-Loaf Islands, from Waireka Hill.
Sugar Loaf Islands, New Plymouth, New Plymouth District, Taranaki Region, New Zealand
Sugar Loaf Islands, New Plymouth, New Plymouth District, Taranaki Region, New Zealand
Formula:
K3Al5(PO3OH)6(PO4)2 · 18H2O
K may be partially replaced by NH4.
Colour:
Yellow, gray, white
Specific Gravity:
2.12 - 2.15
Crystal System:
Trigonal
Name:
Discovered by H. Richmond and described by James Hector in 1865. The mineral is named after its discovery locality, Sugar Loaves, Taranaki peninsula, New Zealand.
A secondary mineral formed from the interaction of phosphatic solutions derived from bird or bat guano on clays or aluminous rocks under perennially damp conditions in caves and along sea coasts.
The K analogue of macivorite.
Partial dehydration leads to francoanellite.
The K analogue of macivorite.
Partial dehydration leads to francoanellite.
Unique Identifiers
Mindat ID:
3890
Long-form identifier:
mindat:1:1:3890:0
IMA Classification of Taranakite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
K3Al5(PO3OH)6(PO4)2·18H2O
First published:
1865
Classification of Taranakite
8.CH.25
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
H : With large and medium-sized cations, RO4:H2O < 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
H : With large and medium-sized cations, RO4:H2O < 1:1
39.3.6.1
39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
3 : Miscellaneous
39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
3 : Miscellaneous
19.8.7
19 : Phosphates
8 : Phosphates of Al and other metals
19 : Phosphates
8 : Phosphates of Al and other metals
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Tar | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Taranakite
Transparency:
Transparent
Colour:
Yellow, gray, white
Comment:
Colourless in transmitted light.
Tenacity:
Malleable
Density:
2.12 - 2.15 g/cm3 (Measured) 2.12 g/cm3 (Calculated)
Optical Data of Taranakite
Type:
Uniaxial (-)
RI values:
nω = 1.506 - 1.51 nε = 1.5 - 1.503
Max. Birefringence:
δ = 0.006 - 0.007
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
Surface Relief:
Moderate
Chemistry of Taranakite
Mindat Formula:
K3Al5(PO3OH)6(PO4)2 · 18H2O
K may be partially replaced by NH4.
K may be partially replaced by NH4.
Element Weights:
Common Impurities:
N
Crystallography of Taranakite
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3c
Cell Parameters:
a = 8.7025 Å, c = 95.05 Å
Ratio:
a:c = 1 : 10.922
Unit Cell V:
6,234.06 ų (Calculated from Unit Cell)
Z:
6
Morphology:
Crystals pseudohexagonal, platy; minute, lath-like and commonly in compact nodular aggregates, powdery, flour-like to claylike; massive.
Comment:
Space group determined from synthetic material.
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0012725 | Taranakite | Dick S, Gossner U, Weiss A, Robl C, Grossman G, Ohms G, Zeiske T (1998) Taranakite - the mineral with the longest crystallographic axis Inorganica Chimica Acta 269 47-57 | 1998 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 15.82 Å | (100) |
| 3.82 Å | (40) |
| 3.14 Å | (31) |
| 3.36 Å | (29) |
| 7.47 Å | (28) |
| 3.59 Å | (22) |
| 7.92 Å | (18) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| 52 : Guano- and urine-derived minerals | <0.4 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Taranakite
Place of Conservation of Type Material:
No designated type material.
Geological Setting of Type Material:
Thin seams in fissures in trachytic rocks, with phosphate derived from guano.
Associated Minerals at Type Locality:
Synonyms of Taranakite
Other Language Names for Taranakite
Common Associates
Associations Based on Photo Data:
| 2 photos of Taranakite associated with Parwanite | (Na,K)(Mg,Ca)4Al8(PO4)8(CO3)(OH)7 · 30H2O |
| 1 photo of Taranakite associated with Montgomeryite | Ca4MgAl4(PO4)6(OH)4 · 12H2O |
| 1 photo of Taranakite associated with Montmorillonite | (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O |
Related Minerals - Strunz-mindat Grouping
| 8.CH.05 | Natrowalentaite | [Fe3+0.5Na0.5(H2O)6][NaAs3+2(Fe3+2.33W6+0.67)(PO4)2O7] |
| 8.CH.05 | Walentaite | [Mn2+(H2O)6][◻As3+3Fe3+3(PO4)2O7] |
| 8.CH.05 | Halilsarpite | [Mg(H2O)6][CaAs3+2(Fe3+2.67Mo6+0.33)(AsO4)2O7] |
| 8.CH.10 | Anapaite | Ca2Fe2+(PO4)2 · 4H2O |
| 8.CH.15 | Picropharmacolite | Ca4Mg(AsO4)2(HAsO4)2 · 11H2O |
| 8.CH.20 | Dittmarite | (NH4)Mg(PO4) · H2O |
| 8.CH.20 | Niahite | (NH4)Mn2+(PO4) · H2O |
| 8.CH.25 | Francoanellite | K3Al5(PO3OH)6(PO4)2 · 12H2O |
| 8.CH.25 | Macivorite | (NH4)3Al5(PO3OH)6(PO4)2 · 18H2O |
| 8.CH.30 | Schertelite | (NH4)2MgH2(PO4)2 · 4H2O |
| 8.CH.35 | Hannayite | (NH4)2Mg3H4(PO4)4 · 8H2O |
| 8.CH.40 | Hazenite | KNaMg2(PO4)2 · 14H2O |
| 8.CH.40 | Struvite-(K) | KMg(PO4) · 6H2O |
| 8.CH.40 | Struvite | (NH4)Mg(PO4) · 6H2O |
| 8.CH.45 | Rimkorolgite | (Mg,Mn)5(Ba,Sr,Ca)(PO4)4 · 8H2O |
| 8.CH.50 | Bakhchisaraitsevite | Na2Mg5(PO4)4 · 7H2O |
| 8.CH.55 | Smolyaninovite | Co3Fe3+2(AsO4)4 · 11H2O |
| 8.CH.55 | Fahleite | CaZn5Fe3+2(AsO4)6 · 14H2O |
| 8.CH.60 | Barahonaite-(Fe) | (Ca,Cu,Na,Fe3+,Al)12Fe3+2(AsO4)8(OH,Cl)x · nH2O |
| 8.CH.60 | Barahonaite-(Al) | (Ca,Cu,Na,Fe3+,Al)12Al2(AsO4)8(OH,Cl)x · nH2O |
| 8.CH.70 | Epifanovite | NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O |
| 8.CH.75 | Esdanaite-(Ce) | NaMnCe(PO4)2 · 4H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 8.7384% | 2,709 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Other Information
Notes:
Readily soluble in acids.
Easily fusible (distinguishing it from visually similar wavellite).
Easily fusible (distinguishing it from visually similar wavellite).
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 Taranakite
mindat.org URL:
https://www.mindat.org/min-3890.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Taranakite
Reference List:
Bannister, F. A., Hutchinson, G. E. (1947) The identity of minervite and palmerite with taranakite. Mineralogical Magazine and Journal of the Mineralogical Society, 28 (196) 31-35 doi:10.1180/minmag.1947.028.196.07
Muray, John W., Dietrich, Richard V. (1956) Brushite and taranakite from Pig Hole Cave, Giles County, Virginia. American Mineralogist, 41 (7-8) 616-626
Smith, J. P., Brown, W. E. (1959) X-ray studies of aluminum and iron phosphates containing potassium or ammonium. American Mineralogist, 44 (1-2). 138-142
Sakae, Toshiro, Sudo, Toshio (1975) Taranakite from the Onino-Iwaya limestone cave at Hiroshima Prefecture, Japan: A new occurrence. American Mineralogist, 60 (3-4) 331-334
Fiore, Saverio, Laviano, Rocco (1991) Brushite, hydroxylapatite, and taranakite from Apulian caves (southern Italy): New mineralogical data. American Mineralogist, 76 (9-10) 1722-1727
Dick, Stefan, Goβner, Ursula, Weiβ, Armin, Robl, Christian, Groβmann, Gisbert, Ohms, Gisela, Zeiske, Thomas (1998) Taranakite — the mineral with the longest crystallographic axis. Inorganica Chimica Acta, 269 (1). 47-57 doi:10.1016/s0020-1693(97)05781-2
Dick, Stefan, Zeiske, Thomas (1998) Francoanellit K3Al5HPO4)6(PO4)2 · 12H2O: Struktur und Synthese durch topochemische Entwässerung von Taranakit / Francoanellite K3Al5HPO4)6(PO4)2 · 12H2O: Structure and Synthesis by Topochemical Dehydration of Taranakite. Zeitschrift für Naturforschung B, 53. 711-719 doi:10.1515/znb-1998-0711
Zhou, J. M., Liu, C., Huang, P. M. (2000) Perturbation of Taranakite Formation by Ferrous and Ferric Iron under Acidic Conditions. Soil Science Society of America Journal, 64 (3). 885-892 doi:10.2136/sssaj2000.643885x
Willems, L., Compère, Ph., Hatert, F., Pouclet, A., Vicat, J. P., Ek, C., Boulvain, F. (2002) Karst in granitic rocks, South Cameroon: cave genesis and silica and taranakite speleothems. Terra Nova, 14 (5). 355-362 doi:10.1046/j.1365-3121.2002.00429.x
Localities for Taranakite
Showing 72 localities.
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Algeria | |
| A. Carnot +1 other reference |
Antarctica | |
| Tatur et al. (1985) +1 other reference |
Argentina | |
| L. R. Catalano +1 other reference |
Australia | |
| Palache et al. (1951) +1 other reference |
| Webb et al. (1982) |
| Birch et al. (1993) |
| Helictite 13:19-33 |
| Bridge et al. (1978) |
Brazil | |
| Piló et al. (2023) |
| Piló et al. (2023) |
Cameroon | |
| Willems et al. (2002) |
Chile | |
| XRD and SEM-EDS by Igor V. Pekov |
China | |
| Xunyi Wang (1982) |
Czech Republic | |
| Hršelová et al. (2013) |
France | |
| Bannister (1947) +4 other references |
| Palache et al. (1951) | |
Germany | |
| Blaß et al. (1995) |
| EDX and XRD confirmed by Dr. Th. Witzke |
Greece | |
| Natural History Museum Vienna collection (collected by Robert Seemann in 2006, PXRD-analysed by Christian L. Lengauer, University of Vienna) |
Hungary | |
| Sándor et al. (2005) |
| Audra et al. (2019) |
Iran | |
| Amin et al. (2022) |
Israel | |
| Weiner et al. (1993) |
Italy | |
| Dell'Anna et al. (1989) |
| Balenzano et al. (1974) |
| Dell'Anna et al. (1989) |
| Dell'Anna et al. (1989) |
| Dell'Anna et al. (1989) | |
| Dell'Anna et al. (1989) | |
| Casoria (1904) +2 other references |
| Audra et al. (2019) |
| Cancian (1984) |
| Baldoni et al. (2013) +2 other references |
| Audra et al. (2019) |
| Audra et al. (2019) |
| Vattano M. et al. (2013) | |
Japan | |
| Sakae et al. (1975) +1 other reference |
| Nobuhide Sawamura & Hitoshi Momoi: ... +1 other reference |
| Ohe Rikosha specimens | |
Kenya | |
| Forti et al. (2004) |
Kyrgyzstan | |
| V.I. Stepanov data |
Malaysia | |
| Bridge et al. (1983) |
Mexico | |
| Forti (2006) |
New Zealand | |
| J. Thornton in Micro-Scope +1 other reference |
| Palache et al. (1951) +2 other references |
Philippines | |
| Wurster et al. (2015) |
| Wurster et al. (2015) |
Romania | |
| al României (2003) |
| Dumitraş et al. (2025) |
| Dumitras D et al. (2004) |
| Marincea et al. (2006) |
| Dumitras et al. (2000) +1 other reference |
| Onac (2009) |
| Neacșu Antonela (2007) |
| Marincea et al. (2004) +1 other reference |
| Onac et al. (2003) |
| Tudor Tămaș (2010) | |
Russia | |
| Sokol et al. (2022) |
Slovakia | |
| Sejkora et al. (2004) +1 other reference |
South Africa | |
| Martini et al. (1978) |
| Martini (1997) |
| Martini et al. (1978) |
| Martini et al. (1978) |
| Miller et al. (2016) |
South Korea | |
| Jun +4 other references |
Spain | |
| B. Onac et al (2009) |
| Onac et al. (2005) |
USA | |
| Hanna (1951) +2 other references |
| NSS Bulletin 44:90-97 (1982) |
| Muray et al. (1956) |
| Dietrich (1990) |
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Parwan lava caves, Parwan, Moorabool Shire, Victoria, Australia