Dachiardite-Ca
A valid IMA mineral species - grandfathered
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About Dachiardite-Ca
Antonio D'Achiardi
Formula:
(Ca,Na2,K2)5Al10Si38O96 · 25H2O
Colour:
Colorless
Lustre:
Vitreous
Hardness:
4 - 4½
Specific Gravity:
2.165 - 2.206
Crystal System:
Monoclinic
Member of:
Name:
Named after Antonio D'Achiardi (1839–1902), Professor of Mineralogy, Universitá di Pisa, Italy, who first described the mineral discovered by his son in a granitic pegmatite. Originally named only dachiardite, it was renamed in 1997 as dachiardite-Ca by the IMA.
Unique Identifiers
Mindat ID:
6895
Long-form identifier:
mindat:1:1:6895:2
Similar Names
| Dachiardita-K | A synonym of Dachiardite-K | |
| Dachiardite-Na | A valid IMA mineral species | (Na2,Ca,K2)5Al10Si38O96 · 25H2O |
IMA Classification of Dachiardite-Ca
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Renamed by the IMA
IMA Formula:
Ca2(Si20Al4)O48·13H2O
First published:
1906
Approval history:
Renamed Dachiardite-Ca in 1997 (IMA special procedure)
Classification of Dachiardite-Ca
9.GD.40
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
D : Chains of 6-membered rings – tabular zeolites
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
D : Chains of 6-membered rings – tabular zeolites
77.1.24.2
77 : TECTOSILICATES Zeolites
1 : Zeolite group - True zeolites
77 : TECTOSILICATES Zeolites
1 : Zeolite group - True zeolites
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 |
|---|---|---|
| Dac-Ca | 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 Dachiardite-Ca
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
4 - 4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {001}, {100}
On {001}, {100}
Fracture:
Irregular/Uneven, Conchoidal
Density:
2.165 - 2.206 g/cm3 (Measured) 2.1395(15) g/cm3 (Calculated)
Optical Data of Dachiardite-Ca
Type:
Biaxial (+)
RI values:
nα = 1.488 - 1.494 nβ = 1.49 - 1.496 nγ = 1.494 - 1.499
2V:
Measured: 58° to 73°, Calculated: 72° to 80°
Max. Birefringence:
δ = 0.005 - 0.006
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate (negative)
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
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v strong
Chemistry of Dachiardite-Ca
Mindat Formula:
(Ca,Na2,K2)5Al10Si38O96 · 25H2O
Element Weights:
Crystallography of Dachiardite-Ca
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 18.625 Å, b = 7.508 Å, c = 10.247 Å
β = 108.056°
β = 108.056°
Ratio:
a:b:c = 2.481 : 1 : 1.365
Unit Cell V:
1,362.34 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Typically as bladed prismatic crystals, commonly fibrous. Radiating aggregates.
Twinning:
Material from Elba exhibits twinning on {110} as rare cyclical eightlings.
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) |
|---|---|---|---|---|---|---|---|
| 0006381 | Dachiardite-Ca | Quartieri S, Vezzalini G, Alberti A (1990) Dachiardite from Hokiya-dake: evidence of a new topology European Journal of Mineralogy 2 187-193 | 1990 | Hokiya-dake, Japan | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.452 Å | (100) |
| 3.204 Å | (100) |
| 1.873 Å | (75) |
| 8.90 Å | (50) |
| 6.91 Å | (50) |
| 4.97 Å | (50) |
| 4.88 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 10 : Basalt-hosted zeolite minerals | |
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 14 : Hot springs, geysers, and other subaerial geothermal minerals | |
| 16 : Low-? aqueous alteration of Hadean subaerial lithologies (see also #23) | |
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Type Occurrence of Dachiardite-Ca
Place of Conservation of Type Material:
Natural History Museum, Paris, France, 109.1084.
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 123998.
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 123998.
Other Language Names for Dachiardite-Ca
Relationship of Dachiardite-Ca to other Species
Member of:
Other Members of Dachiardite Subgroup:
| Dachiardite-K | K4(Si20Al4O48) · 13H2O | Mon. |
| Dachiardite-Na | (Na2,Ca,K2)5Al10Si38O96 · 25H2O | Mon. 2/m : B2/m |
Common Associates
Associations Based on Photo Data:
| 31 photos of Dachiardite-Ca associated with Mordenite | (Na2,Ca,K2)4(Al8Si40)O96 · 28H2O |
| 19 photos of Dachiardite-Ca associated with Dachiardite-Na | (Na2,Ca,K2)5Al10Si38O96 · 25H2O |
| 12 photos of Dachiardite-Ca associated with Clinoptilolite-Ca | Ca3(Si30Al6)O72 · 20H2O |
| 7 photos of Dachiardite-Ca associated with 'Chalcedony' | SiO2 |
| 5 photos of Dachiardite-Ca associated with Saponite | Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2 · nH2O |
| 4 photos of Dachiardite-Ca associated with Ferrierite-Na | (Na,K)5(Si31Al5)O72 · 18H2O |
| 4 photos of Dachiardite-Ca associated with Pyrite | FeS2 |
| 3 photos of Dachiardite-Ca associated with Stilbite Subgroup | M6-7[Al8-9Si27-28O72] · nH2O |
| 2 photos of Dachiardite-Ca associated with Phillipsite-Ca | Ca3(Si10Al6)O32 · 12H2O |
| 1 photo of Dachiardite-Ca associated with Calcite | CaCO3 |
Related Minerals - Strunz-mindat Grouping
| 9.GD.05 | Gmelinite-Ca | Ca2(Si8Al4)O24 · 11H2O |
| 9.GD.05 | Gmelinite-K | K4(Si8Al4O24) · 11H2O |
| 9.GD.05 | Gmelinite-Na | Na4(Si8Al4)O24 · 11H2O |
| 9.GD.10 | Chabazite-Mg | (Mg0.7K0.5Ca0.5Na0.1)[Al3Si9O24] · 10H2O |
| 9.GD.10 | Willhendersonite | KCa[Al3Si3O12] · 5H2O |
| 9.GD.10 | Chabazite-Ca | (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O |
| 9.GD.10 | Chabazite-K | (K2,Ca,Na2,Sr,Mg)2[Al2Si4O12]2 · 12H2O |
| 9.GD.10 | Chabazite-Na | (Na2,K2,Ca,Sr,Mg)2[Al2Si4O12]2 · 12H2O |
| 9.GD.10 | Chabazite-Sr | Sr2[Al2Si4O12]2 · 12H2O |
| 9.GD.15 | Lévyne-Ca | (Ca,Na2,K2)[Al2Si4O12] · 6H2O |
| 9.GD.15 | Lévyne-Na | (Na2,Ca,K2)[Al2Si4O12] · 6H2O |
| 9.GD.20 | Erionite-Ca | (Ca,K2,Na2)2[Al4Si14O36] · 15H2O |
| 9.GD.20 | Erionite-K | (K2,Ca,Na2)2[Al4Si14O36] · 15H2O |
| 9.GD.20 | Erionite-Na | (Na2,K2,Ca)2[Al4Si14O36] · 15H2O |
| 9.GD.20 | Bellbergite | (K,Ba,Sr)2Sr2Ca2(Ca,Na)4[Al3Si3O12]6 · 30H2O |
| 9.GD.25 | Offretite | KCaMg(Si13Al5)O36 · 15H2O |
| 9.GD.25 | Wenkite | (Ba,K)4(Ca,Na)6[(Si,Al)20O39(OH)2](SO4)3 · 0.5H2O |
| 9.GD.30 | Faujasite-Ca | (Ca,Na2,Mg)3.5[Al7Si17O48] · 32H2O |
| 9.GD.30 | Faujasite-Mg | (Mg,Na2,Ca)3.5[Al7Si17O48] · 32H2O |
| 9.GD.30 | Faujasite-Na | (Na2,Ca,Mg)3.5[Al7Si17O48] · 32H2O |
| 9.GD.35 | Maricopaite | Pb7Ca2(Si,Al)48O100 · 32H2O |
| 9.GD.35 | Mordenite | (Na2,Ca,K2)4(Al8Si40)O96 · 28H2O |
| 9.GD.40 | Dachiardite-K | K4(Si20Al4O48) · 13H2O |
| 9.GD.40 | Dachiardite-Na | (Na2,Ca,K2)5Al10Si38O96 · 25H2O |
| 9.GD.45 | Epistilbite | CaAl2Si6O16 · 5H2O |
| 9.GD.50 | Ferrierite-K | (K,Na)5(Si31Al5)O72 · 18H2O |
| 9.GD.50 | Ferrierite-Mg | [Mg2(K,Na)2Ca0.5](Si29Al7)O72 · 18H2O |
| 9.GD.50 | Ferrierite-Na | (Na,K)5(Si31Al5)O72 · 18H2O |
| 9.GD.50 | Ferrierite-NH4 | (NH4,Mg0.5)5(Al5Si31O72) · 22H2O |
| 9.GD.55 | Bikitaite | LiAlSi2O6 · H2O |
Other Information
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 Dachiardite-Ca
mindat.org URL:
https://www.mindat.org/min-6895.html
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References for Dachiardite-Ca
Reference List:
Bonardi, Maurizio (1979) Composition of type dachiardite from Elba: a re-examination. Mineralogical Magazine, 43 (328) 548-549 doi:10.1180/minmag.1979.043.328.19
Vezzalini, G. (1984) A refinement of Elba dachiardite : Opposite acentric domains simulating a centric structure. Zeitschrift für Kristallographie, 166 (1-4). 63-71 doi:10.1524/zkri.1984.166.14.63
Bargar, K. E., Erd, R. C., Keith, T. E. C., Beeson, M. H. (1987) Dachiardite from Yellowstone National Park, Wyoming. The Canadian Mineralogist, 25 (3) 475-483
Quartieri, Simona, Vezzalini, Giovanna, Alberti, Alberto (1990) Dachiardite from Hokiya-dake: evidence of a new topology. European Journal of Mineralogy, 2 (2) 187-193 doi:10.1127/ejm/2/2/0187
Coombs, Douglas S., Alberti, Alberto, Armbruster, Thomas, Artioli, Gilberto, Colella, Carmine, Galli, Ermanno, Grice, Joel D., Liebau, Friedrich, Mandarino, Joseph A., Minato, Hideo, et al. (1997) Recommended nomenclature for zeolite minerals; report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35 (6). 1571-1606
Localities for Dachiardite-Ca
Showing 20 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.
Bulgaria | |
| Gellens et al. (1982) |
| Encheva | |
Canada | |
| 176-178. +1 other reference |
Czech Republic | |
| Pauliš P. et al. (2007) |
| Pauliš P. et al. (2007) |
| Rychlý et al. (1996) |
| P.Pauliš et al. (2014) |
Germany | |
| Belendorff (2021) |
Hungary | |
| Sándor et al. (2005) |
Italy | |
| G. D'Achiardi (1905) |
| Orlandi P. & Pezzotta (1996) | |
| Orlandi P. & Pezzotta (1996) +1 other reference | |
| Fabio Tosato et al. (2024) |
Japan | |
| Quartieri et al. (1990) |
| Quartieri et al. (1990) |
Slovakia | |
| Myšľan P et al. (2022) |
| Myšľan P et al. (2022) | |
USA | |
| Micro Probe Volume IX Number 3 |
| Micro Probe Volume IX Number 3 Spring ... |
| - (n.d.) |
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Unnamed Basalt quarry, Altoona, Wahkiakum County, Washington, USA