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Ferri-pedrizite

A valid IMA mineral species

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Discuss Ferri-pedrizite

Edit Ferri-pedrizite Add Synonym Edit CIF structures Clear Cache

Formula:

NaLi₂(Mg₂Fe³⁺₂Li)Si₈O₂₂(OH)₂

The pedrizite group minerals are lithium amphiboles defined with:
^A(Na+K+2Ca)> 0.5 apfu and
^CLi > 0.5 apfu

Ferri-pedrizite is defined with
A position: Na dominant
C²⁺ position: Mg dominant
C³⁺ position: Fe dominant
W position: (OH) dominant

Colour:

Green, black

Lustre:

Vitreous

Hardness:

Specific Gravity:

3.15

Crystal System:

Monoclinic

Member of:

Pedrizite Root Name Group > Lithium Amphibole Subgroup > w(OH,F,Cl)-dominant Amphibole Group > Amphibole Supergroup

This page provides mineralogical data about Ferri-pedrizite.

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Unique IdentifiersHide

Mindat ID:

10406

Long-form identifier:

mindat:1:1:10406:5

Similar NamesHide

Ferripedrizit	A synonym of 'Sodic-ferripedrizite'
Ferro-pedrizite	A valid IMA mineral species	NaLi₂(Fe₂²⁺Al₂Li)Si₈O₂₂(OH)₂

IMA Classification of Ferri-pedriziteHide

IMA status:

Approved

IMA status notes:

Redefined by the IMA, Published without approval

IMA Formula:

LiNa₂(Fe³⁺₂Mg₂Li)Si₈O₂₂(OH)₂

Approval history:

Originally published without approval. Validated by CNMNC amphibole nomenclature revision (Hawthorne et al., 2012)
IMA list gives Redefined 2012 s.p.

Classification of Ferri-pedriziteHide

Strunz-mindat (2026):

9.DE.25

9 : SILICATES (Germanates)
D : Inosilicates
E : Inosilicates with 2-periodic double chains, Si₄O₁₁; Clinoamphiboles

Mineral SymbolsHide

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
Fpd	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 Ferri-pedriziteHide

Lustre:

Vitreous

Colour:

Green, black

Streak:

Gray

Hardness:

6 on Mohs scale

Cleavage:

Perfect
on {110}

Density:

3.15 g/cm³ (Measured) 3.19 g/cm³ (Calculated)

Optical Data of Ferri-pedriziteHide

Type:

Biaxial (-)

RI values:

n_α = 1.694 n_β = 1.698 n_γ = 1.702

2V:

Measured: 83° , Calculated: 88°

Max. Birefringence:

δ = 0.008
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.

Thickness: 30 µm Order divisions

Rotation:

Surface Relief:

Very High (positive)
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.

Focus:

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.

Thickness: 30 µm

Stage rotation: 0°

Dispersion:

r > v medium

Chemistry of Ferri-pedriziteHide

Mindat Formula:

NaLi₂(Mg₂Fe³⁺₂Li)Si₈O₂₂(OH)₂

The pedrizite group minerals are lithium amphiboles defined with:
^A(Na+K+2Ca)> 0.5 apfu and
^CLi > 0.5 apfu

Ferri-pedrizite is defined with
A position: Na dominant
C²⁺ position: Mg dominant
C³⁺ position: Fe dominant
W position: (OH) dominant

Element Weights:

Element	% weight
O	47.127 %
Si	27.575 %
Fe	13.708 %
Mg	5.966 %
Na	2.822 %
Li	2.556 %
H	0.247 %

Calculated from ideal end-member formula.

Elements listed:

Fe, H, Li, Mg, Na, O, Si - search for minerals with similar chemistry

Chemical AnalysisHide

Oxide wt%:

	1
SiO₂	57.70 %
TiO₂	1.04 %
Al₂O₃	1.26 %
Fe₂O₃	15.81 %
FeO	2.79 %
MnO	0.58 %
MgO	8.45 %
ZnO	0.12 %
CaO	0.56 %
Li₂O	3.98 %
Na₂O	4.78 %
K₂O	0.15 %
H₂O	1.46 %
F	1.48 %
Total:	100.16 %

Empirical formulas:

Sample ID	Empirical Formula
1	A(Na 0.70K 0.03) B(Li 1.34Na0.58Ca 0.08) (Mg1.75 Fe3+1.65Li 0.88Fe2+0.32Al0.21Ti0.11Mn2+0.07Zn0.01)Si 8.00O22(OH1.35F0.65) ·

Sample references:

ID	Locality	Reference	Notes
1	Arroyo de la Yedra, Manzanares el Real, Community of Madrid, Spain	Oberti, Roberta, Caballero, José M., Ottolini, Luisa, López-Andrés, Sol, Herreros, Victor (2000) Sodic-ferripedrizite, a new monoclinic amphibole bridging the magnesium-iron-manganese-lithium and the sodium-calcium groups. American Mineralogist, 85 (3) 578-585 doi:10.2138/am-2000-0420	The analyses where performed on different sample containing granular aggregates of subhedral crystals of mean size 0.18(11) ´ 0.10(6) mm2. The following analytical techniques were used for this sample: - Wavelength-dispersive analyses on grain-mount thin sections were obtained with a JEOL-8900M electron-microprobe at the Universidad Complutense of Madrid - The crystals used for crystal-structure refinement were subsequently mounted, polished, and analyzed by ion-microprobe techniques to quantify in-situ light and volatile elements (Li, H, F, and Cl). Ion-microprobe analysis was done at CSCC on a Cameca IMS 4f probe - The X-ray powder-diffraction pattern was recorded from a mineral separate with a Philips X-PERT diffractometer with graphite-monochromatized CuKa X-radiation Further details on the analytical methods can be found in the reference

Crystallography of Ferri-pedriziteHide

Crystal System:

Monoclinic

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Near-surface Processes
22 : Hydration and low-? subsurface aqueous alteration (see also #23)
Stage 4b: Highly evolved igneous rocks	>3.0
34 : Complex granite pegmatites

Synonyms of Ferri-pedriziteHide

Sodic-ferripedrizite

Sodic amphibole (in part)

Sodicpedrizite (in part)

Other Language Names for Ferri-pedriziteHide

German:Natrium-Ferripedrizit

Russian:Натроферрипедрисит

Spanish:Ferri-pedrizita

Relationship of Ferri-pedrizite to other SpeciesHide