Sunday, 3 February 2013

Aeschynite

1:37 pm OHM

Lohning quarry (Lohninger quarry), Hüttwinkl valley, Rauris valley, Hohe Tauern, Salzburg, Austria
© Stephan Wolfsried

Formula: (Y,Ca,Fe,Th)(Ti,Nb)2(O,OH)6
System: Orthorhombic
Colour: Pale yellow, ...
Lustre: Resinous, Waxy, Pearly, Sub-Metallic
Hardness: 5 - 6
Member of: Aeschynite Group
Name: For its relationship to Aeschynite-(Ce), with yttrium as the dominant rare-earth element.

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Type Occurrence of Aeschynite-(Y)

Type Locality: Urstad feldspar quarry, Hidra (Hitterø), Flekkefjord, Vest-Agder, Norway

Occurrences of Aeschynite-(Y)

Geological Setting: In granite and granite pegmatites, in ankerite-dolomitic carbonatites, as a detrital mineral in placers.

Physical Properties of Aeschynite-(Y)

Lustre: Resinous, Waxy, Pearly, Sub-Metallic
Diaphaneity (Transparency): Transparent, Translucent
Comment: Submetallic to pearly on crystal faces, resinous to waxy on fracture surfaces.
Colour: Pale yellow, yellow-orange, pale greenish yellow
Streak: White, pale yellow, reddish yellow
Hardness (Mohs): 5 - 6
Tenacity: Brittle
Cleavage: Perfect
on {100}, {010} and {001}
Fracture: Irregular/Uneven
Density (measured): 4.82 - 4.93 g/cm3
Density (calculated): 5.5 g/cm3

Chemical Properties of Aeschynite-(Y)

Formula: (Y,Ca,Fe,Th)(Ti,Nb)2(O,OH)6Essential elements: O, Ti, Y
All elements listed in formula: Ca, Fe, H, Nb, O, Th, Ti, Y
Analytical Data: Sample from Urstad, Norway; "Ce2O3" includes (La,Dy)2O3

Nb2O5 (17.99)
Ta2O5 (0.89)
SiO2 (0.38)
TiO2 (32.91)
SnO2 (0.12)
ThO2 (7.69)
UO2 (4.01)
(Y,Er)2O3 (28.76)
Ce2O3 (1.97)
FeO (1.48)
MnO (0.27)
PbO (0.06)
MgO (0.04)
CaO (1.02)
Na2O (0.22)
K2O (0.19)
H2O (1.88)

sum 99.88 wt.-%

Photos :

This sample of aeschynite is from the same location. It is about 7 x 14 cm

This sample of aeschynite is displayed in the Smithsonian Museum of Natural History. Aeschynite contains yttrium, thorium, titanium, and niobium along with iron and calcium. It has the composition (Y,Ca,Fe,Th)(Ti,Nb)2(O,OH)6. This sample is about 3x4.5 cm and it is from Ivelanc, Setesdal, Norway .

More Info > Mindat: Aeschynite