Rhodizite
A valid IMA mineral species - grandfathered
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About Rhodizite
Formula:
KBe4Al4(B11Be)O28
Colour:
Colourless, white, greyish, yellowish; colourless in transmitted light
Lustre:
Adamantine, Vitreous
Hardness:
8
Specific Gravity:
3.305 - 3.38
Crystal System:
Isometric
Name:
From the Greek, "rhodizein," = "to be rose-coloured" in allusion to its property of turning a blowpipe flame rose-red. Do not confuse with rhodesite.
The potassium analogue of Londonite. Londonite-Rhodizite Series.
First described by Rose in 1834 without quantitative chemical data. A chemical analysis was made by Damour (1882) but later showed to be incomplete, lacking both Li and Be. The alkali metals were also not separated in the analysis. Pekov et al. (2010) re-analyzed co-type specimens of rhodizite from Sarapulsk and Shaitanka, Russia and found all to be Cs-dominant (Cs > K) and thus londonite according to IMA nomenclature. No rhodizite has been verified from the co-type localities. However, K-dominant members of the londonite-rhodizite series have been noted from Madagascar.
Note: Both K-dominant and Cs-dominant samples from Madagascar prior to the description of londonite (the Cs-dominant member of the londonite-rhodizite series) by Simmons et al. (2001) have been described as rhodizite in the literature.
NOTE:
Specimens from Madagascar without analysis should be labeled as londonite-rhodizite series. Many crystals contain complex patchy zones of londonite and rhodizite which are only visible by back-scattered electron imaging (Simmons et al. 2001).
Visit gemdat.org for gemological information about Rhodizite.
First described by Rose in 1834 without quantitative chemical data. A chemical analysis was made by Damour (1882) but later showed to be incomplete, lacking both Li and Be. The alkali metals were also not separated in the analysis. Pekov et al. (2010) re-analyzed co-type specimens of rhodizite from Sarapulsk and Shaitanka, Russia and found all to be Cs-dominant (Cs > K) and thus londonite according to IMA nomenclature. No rhodizite has been verified from the co-type localities. However, K-dominant members of the londonite-rhodizite series have been noted from Madagascar.
Note: Both K-dominant and Cs-dominant samples from Madagascar prior to the description of londonite (the Cs-dominant member of the londonite-rhodizite series) by Simmons et al. (2001) have been described as rhodizite in the literature.
NOTE:
Specimens from Madagascar without analysis should be labeled as londonite-rhodizite series. Many crystals contain complex patchy zones of londonite and rhodizite which are only visible by back-scattered electron imaging (Simmons et al. 2001).
Visit gemdat.org for gemological information about Rhodizite.Unique Identifiers
Mindat ID:
3405
Long-form identifier:
mindat:1:1:3405:6
Similar Names
| Magnesio-riebeckite | A valid IMA mineral species - grandfathered | ◻Na2(Mg3Fe23+)(Si8O22)(OH)2 |
| Rhodesite | A valid IMA mineral species - grandfathered | KHCa2Si8O19 · 5H2O |
| Rhätizit | A synonym of 'Rhätizite' |
IMA Classification of Rhodizite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
KAl4Be5B11O28
First published:
1834
Classification of Rhodizite
6.GC.05
6 : BORATES
G : Heptaborates and other megaborates
C : Tekto-dodecaborates
6 : BORATES
G : Heptaborates and other megaborates
C : Tekto-dodecaborates
25.8.2.1
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
8 : Miscellaneous
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
8 : Miscellaneous
9.1.16
9 : Borates
1 : Borates of the alkalis and boric acid
9 : Borates
1 : Borates of the alkalis and boric acid
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Rdz | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Rdz | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Rhodizite
Adamantine, Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless, white, greyish, yellowish; colourless in transmitted light
Streak:
White
Hardness:
8 on Mohs scale
Cleavage:
Distinct/Good
On {111} and {1_11}, difficult.
On {111} and {1_11}, difficult.
Fracture:
Conchoidal
Density:
3.305 - 3.38 g/cm3 (Measured) 3.24 g/cm3 (Calculated)
Optical Data of Rhodizite
Type:
Isotropic
RI values:
n = 1.689 - 1.691
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Comments:
Exhibits weak anomalous double refraction distributed in sectors with Z(+) inclined about 10° to [110].
Chemistry of Rhodizite
Mindat Formula:
KBe4Al4(B11Be)O28
Element Weights:
Common Impurities:
Rb,Na,K
Crystallography of Rhodizite
Crystal System:
Isometric
Class (H-M):
43m - Hextetrahedral
Space Group:
P43m
Cell Parameters:
a = 7.31 Å
Unit Cell V:
390.62 ų (Calculated from Unit Cell)
Morphology:
Crystals dodecahedral, also tetrahedral. "o" usually smooth and shining and "d" frequently uneven. Dodecahedral {110} faces modified by deltoid dodecahedral {221}, tristetrahedral {211}, and tetrahedral {111} faces and rare cubic {100} faces.
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) |
|---|---|---|---|---|---|---|---|
| 0014483 | Rhodizite | Pring A, Din V K, Jefferson D A, Thomas J M (1986) The crystal chemistry of rhodizite: a re-examination Mineralogical Magazine 50 163-172 |  | 1986 | Ambatofinandrahana, Ankarata Mts, Madagascar | 0 | 293 |
| 0015418 | Rhodizite | Buerger M J, Taxer K (1966) Rhodizite. Structure and composition Science 152 500-502 | 1966 | Manjaka, Madagascar | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.983 Å | (100) |
| 2.440 Å | (51) |
| 3.274 Å | (48) |
| 2.111 Å | (37) |
| 1.775 Å | (25) |
| 1.956 Å | (22) |
| 2.205 Å | (21) |
Comments:
Manjaka, Madagascar.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Rhodizite
Co-Type Localities:
Place of Conservation of Type Material:
Museum für Naturkunde, Humboldt-Universität-Berlin, Germany, numbers 1997-4993, 1997-0082, 1997-2275.
Associated Minerals at Type Locality:
Synonyms of Rhodizite
Other Language Names for Rhodizite
Relationship of Rhodizite to other Species
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 27 photos of Rhodizite associated with 'Rubellite' | |
| 16 photos of Rhodizite associated with Tourmaline | AD3G6(T6O18)(BO3)3X3Z |
| 14 photos of Rhodizite associated with Quartz | SiO2 |
| 6 photos of Rhodizite associated with Albite | Na(AlSi3O8) |
| 6 photos of Rhodizite associated with Elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 5 photos of Rhodizite associated with Microcline | K(AlSi3O8) |
| 3 photos of Rhodizite associated with Danburite | CaB2Si2O8 |
| 2 photos of Rhodizite associated with Columbite-(Mn) | Mn2+Nb2O6 |
| 2 photos of Rhodizite associated with K Feldspar | |
| 2 photos of Rhodizite associated with Béhierite | Ta(BO4) |
Related Minerals - Strunz-mindat Grouping
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) | 5.1514% | 1,597 | 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
Fluorescence of Rhodizite
Very weak to moderate yellowish green fluorescence with short-wave UV radiation. Usually no fluorescence with long-wave UV, but occasionally very weak to weak yellowish green (Laurs et al 2002).
Other Information
Electrical:
Pyroelectric.
Notes:
Insoluble in acids.
Naturally colored material fades in sunlight over a period of 2-4 weeks (Laurs et al 2002).
Naturally colored material fades in sunlight over a period of 2-4 weeks (Laurs et al 2002).
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 Rhodizite
mindat.org URL:
https://www.mindat.org/min-3405.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Rhodizite
Reference List:
Rose, Gustav (1834) Ueber den Rhodizit, eine neue Mineralgattung. Annalen der Physik und Chemie, 109. 253-256 doi:10.1002/andp.18341090814
Rose, Gustav (1836) Fernere Bemerkungen über den Rhodizit. Annalen der Physik und Chemie, 115. 321-323 doi:10.1002/andp.18361151007
Riess Rose, P. Gustav (1843) Ueber die Pyroëlektricität der Mineralien. Annalen der Physik und Chemie, 135. 353-390 doi:10.1002/andp.18431350702
Bertrand, Emile (1882) Propriétés optiques de la rhodizite. Bulletin de Minéralogie, 5 (2) 31-32 doi:10.3406/bulmi.1882.1692
Bertrand, Emile (1882) Sur la forme cristalline de la rhodizite. Bulletin de Minéralogie, 5 (3) 72-74 doi:10.3406/bulmi.1882.1705
Damour, Augustin-Alexis (1882) Sur la rhodizite. Bulletin de Minéralogie, 5 (4) 98-103 doi:10.3406/bulmi.1882.1717
Lacroix, Alfred (1910) Nouvelles observations sur les minéraux des pegmatites de Madagascar. Bulletin de Minéralogie, 33 (1) 37-53 doi:10.3406/bulmi.1910.3399
Duparc, Louis, Wunder, Max, Sabot, R. (1911) Contribution à la connaissance des minéraux des pegmatites (Deuxième Note) Bulletin de Minéralogie, 34 (4) 131-139 doi:10.3406/bulmi.1911.3477
Buerger, M. J., Taxer, K. (1966) Rhodizite: Structure and Composition. Science, 152 (3721). 500-502 doi:10.1126/science.152.3721.500
Taxer, Karlheinz J., Buerger, Martin J. (1967) The crystal structure of rhodizite. Zeitschrift für Kristallographie - Crystalline Materials, 125 (125) 423-436 doi:10.1524/zkri.1967.125.125.423
Pring, A., Din, V. K., Jefferson, D. A., Thomas, J. M. (1986) The crystal chemistry of rhodizite: a re-examination. Mineralogical Magazine, 50 (355) 163-172 doi:10.1180/minmag.1986.050.355.22
Hawthorne, Frank C., Jambor, John L., Bladh, Kenneth W., Burke, Ernst A. J., Grice, Joel D., Phillips, Don, Roberts, Andrew C., Schedler, Robert A., E., James (1987) New mineral names. American Mineralogist, 72 (9-10) 1023-1028
Hawthorne, Frank C., Burke, Ernst A. J., Ercit, T. Scott, Grew, Edward S., Grice, Joel D., Jambor, John L., Puziewicz, Jacek, Roberts, Andrew C., Vanko, David A. (1988) New Mineral Names. American Mineralogist, 73 (1-2) 189-199
Simmons, W. B.; Pezzotta, F.; Falster, A. U.; Webber, K. L. (2001) Londonite, a new mineral species: the Cs-dominant analogue of rhodizite from the Antandrokomby granitic pegmatite, Madagascar. The Canadian Mineralogist, 39 (3). 747-755 doi:10.2113/gscanmin.39.3.747
Laurs, Brendan M.; Pezzotta, Federico; Simmons, William B. (Skip); Falster, Alexander U.; Muhlmeister, Sam (2002) Rhodizite-Londonite from the Antsongombato Pegmatite, Central Madagascar. Gems & Gemology, 38 (4). 326-339 doi:10.5741/gems.38.4.326
Pekov, I. V., Yakubovich, O. V., Massa, W., Chukanov, N. V., Kononkova, N. N., Agakhanov, A. A., Karpenko, V. Y. (2010) Londonite from the Urals, and new aspects of the crystal chemistry of the rhodozite-londonite series. The Canadian Mineralogist, 48 (2) 241-254 doi:10.3749/canmin.48.2.241
Frost, Ray L., López, Andrés, Xi, Yunfei, Scholz, Ricardo, Souza, Larissa, Lana, Cristiano (2014) The molecular structure of the borate mineral rhodizite (K,Cs)Al4Be4(B,Be)12O28 – A vibrational spectroscopic study. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 128. 291-294 doi:10.1016/j.saa.2014.02.036
Localities for Rhodizite
Showing 21 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.
Quick NavTopAbout RhodiziteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
Ifasina, Sahatsiho Ambohimanjaka, Ambositra District, Amoron'i Mania, Madagascar