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Quintinite-3T
A structural variant of Quintinite
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About Quintinite-3T
Formula:
Mg4Al2(OH)12CO3 · 4H2O
Colour:
Bright yellow to pale yellow
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
2.14
Crystal System:
Trigonal
Name:
Named after Quintin Wight (b. 1935), of Ottawa, Ontario, Canada, significant contributor to mineral studies at Mont Saint-Hilaire, and author of The Complete Book of Micromounting (1993).
A polytype of Quintinite
The 3T polytype was originally described from Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville Co., Québec, Canada.
The 3T polytype was originally described from Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville Co., Québec, Canada.
Unique Identifiers
Mindat ID:
7266
Long-form identifier:
mindat:1:1:7266:9
Physical Properties of Quintinite-3T
Vitreous
Transparency:
Transparent
Colour:
Bright yellow to pale yellow
Streak:
White
Hardness:
2 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{0001}
{0001}
Fracture:
Irregular/Uneven
Density:
2.14(1) g/cm3 (Measured) 2.14 g/cm3 (Calculated)
Optical Data of Quintinite-3T
Type:
Uniaxial (+/-)
RI values:
nω = 1.533 nε = 1.533
Max. Birefringence:
δ = 0.000
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
Comments:
Most crystals are non-pleochroic, however,one with a Mg:Fe ratio of ~1 is pleochroic, with O = dark green, E = light green.
Chemistry of Quintinite-3T
Mindat Formula:
Mg4Al2(OH)12CO3 · 4H2O
Element Weights:
Crystallography of Quintinite-3T
Crystal System:
Trigonal
Class (H-M):
3 2 - Trapezohedral
Cell Parameters:
a = 10.571 Å, c = 22.71 Å
Ratio:
a:c = 1 : 2.148
Unit Cell V:
2,197.76 ų (Calculated from Unit Cell)
Z:
6
Morphology:
Hexagonal tabular crystals on {0001}, commonly forming rosettes. Common forms are {0001} and {1010}.
Twinning:
None observed.
Comment:
Space group P3112 or P3212.
Epitaxial Relationships of Quintinite-3T
Epitaxial Minerals:
| Donnayite-(Y) | NaCaSr3Y(CO3)6 · 3H2O |
Epitaxy Comments:
Quintinite-3T on donnayite-(Y). See Chao and Gault (1997).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.57 Å | (100) |
| 3.778 Å | (90) |
| 2.570 Å | (40) |
| 2.281 Å | (40) |
| 1.932 Å | (40) |
| 1.524 Å | (20) |
| 1.493 Å | (20) |
Comments:
Poudrette quarry, Mont Saint-Hilaire, Québec, Canada. The data are from Chao and Gault (1997).
Synonyms of Quintinite-3T
Fluorescence of Quintinite-3T
Not fluorescent
Other Information
Notes:
Attacked slightly by 1:1 HCl, strongly by HNO3, and dissolves in 1:1 H2SO4.
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 Quintinite-3T
mindat.org URL:
https://www.mindat.org/min-7266.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Quintinite-3T
Localities for Quintinite-3T
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.
Canada | |
| American Mineralogist: 83: 1347. +1 other reference |
Russia | |
| Stephan Wolfsried collection |
Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada