Log In
Mantienneite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Mantienneite
Joseph Mantienne
Formula:
KMg2Al2Ti(PO4)4(OH)3 · 15H2O
Colour:
Caramel brown to brownish honey brown
Lustre:
Vitreous
Hardness:
2 - 3
Specific Gravity:
2.31
Crystal System:
Orthorhombic
Member of:
Name:
Named in honour of the French mineralogist Dr. Joseph Mantienne (24 Feb 1929 - 30 Oct 2019), Bureau de Recherches Géologiques et Miniéres (BRGM), Orléans, France.
Type Locality:
A vacancy-dominant end-member (possible new mineral) is discussed by Sejkora et al. (2006), based on analytical data of Fransolet et al. (1984).
Compare also benyacarite and paulkerrite.
Compare also benyacarite and paulkerrite.
Unique Identifiers
Mindat ID:
2569
Long-form identifier:
mindat:1:1:2569:6
IMA Classification of Mantienneite
Approved
IMA Formula:
(H2O)2Mg2(Al2Ti4+)(PO4)4(OH)2(H2O)10·4H2O
Approval year:
1983
First published:
1984
Classification of Mantienneite
8.DH.35
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
42.11.21.2
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
19.8.23
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 |
|---|---|---|
| Mtin | 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 Mantienneite
Vitreous
Transparency:
Translucent
Colour:
Caramel brown to brownish honey brown
Streak:
Pale brown with a rose tint.
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect {001} and poor {010}
Perfect {001} and poor {010}
Density:
2.31 g/cm3 (Measured) 2.25 g/cm3 (Calculated)
Optical Data of Mantienneite
Type:
Biaxial (-)
RI values:
nα = 1.564 nγ = 1.598
2V:
Measured: 50° to 60°
Max. Birefringence:
δ = 0.034
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 (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
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
Pleochroism:
Weak
Comments:
X = colorless; Z = very pale yellow
Comments:
Orientation: X = b; Y = c; Z = a
Chemistry of Mantienneite
Mindat Formula:
KMg2Al2Ti(PO4)4(OH)3 · 15H2O
Element Weights:
Crystallography of Mantienneite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pbca
Setting:
Pbca
Cell Parameters:
a = 10.409(2) Å, b = 20.330(4) Å, c = 12.312(2) Å
Ratio:
a:b:c = 0.512 : 1 : 0.606
Unit Cell V:
2,605.40 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.158 Å | (100) |
| 3.076 Å | (60) |
| 10.18 Å | (40) |
| 7.41 Å | (30) |
| 3.104 Å | (30) |
| 2.949 Å | (30) |
| 2.839 Å | (25) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Mantienneite
General Appearance of Type Material:
Radial fibrous spherules to 1 mm
Place of Conservation of Type Material:
National School of Mines, Paris, France
Geological Setting of Type Material:
Forming the matrix of sandy layers in lacustric shales
Associated Minerals at Type Locality:
Anloua, Martap, Vina, Adamawa Region, Cameroon