Adamsite-(Y)
NaY(CO
3
)
2
•
6H
2
O
c 2001-2005 Mineral Data Publishing, version 1
Crystal Data:
Triclinic, pseudo-orthorhombic if twinned.
Point Group: 1.
Crystals are
acicular to fibrous, to 2.5 cm, elongated along [001], flattened on {001}, showing {010} and {001};
in spherical radiating groups, which rarely are reticulated.
Twinning: By reflection on {001},
common.
Physical Properties:
Cleavage: Perfect on {001}; good on {100}, {010}.
Tenacity: Brittle.
Hardness = 3
D(meas.) = 2.27(2)
D(calc.) = 2.27
Optical Properties:
Transparent to translucent. Color: Colorless, white, may be pale pink or
pale purple.
Streak: White.
Luster: Vitreous to pearly.
Optical Class:
Biaxial (+). Orientation: Y = b; Z ∧ a = 14
◦
.
α = 1.480(4)
β = 1.498(2)
γ = 1.571(4)
2V(meas.) = 53(3)
◦
2V(calc.) = 55
◦
Cell Data:
Space Group: P 1.
a = 6.2592(4)
b = 13.0838(7)
c = 13.2271(5)
α = 91.130(1)
◦
β = 103.554(1)
◦
γ = 90.188(1)
◦
Z = 4
X-ray Powder Pattern:
Mont Saint-Hilaire, Canada.
12.81 (100), 6.45 (70), 4.456 (60), 4.291 (60), 2.571 (60), 2.050 (50), 2.869 (30)
Chemistry:
(1)
(2)
CO
2
25.10
25.89
Y
2
O
3
22.88
33.21
Ce
2
O
3
0.37
Nd
2
O
3
1.41
Sm
2
O
3
1.02
Gd
2
O
3
1.92
Tb
2
O
3
0.56
Dy
2
O
3
3.28
(1)
(2)
Ho
2
O
3
0.90
Er
2
O
3
2.83
Tm
2
O
3
0.27
Yb
2
O
3
1.04
CaO
0.05
Na
2
O
8.64
9.11
H
2
O
29.90
31.79
Total
100.17
100.00
(1) Mont Saint-Hilaire, Canada; by electron microprobe, seven analyses on three crystals, CO
2
and H
2
O by TGA, confirmed by IR and crystal-structure analysis; corresponds to Na
1.00
(Y
0.72
Dy
0.06
Er
0.05
Gd
0.04
Nd
0.03
Yb
0.02
Sm
0.02
Ho
0.02
Ce
0.01
Tb
0.01
Tm
0.01
)
Σ=0.99
(CO
3
)
2.04
•
5.94H
2
O.
(2) NaY(CO
3
)
2
•
6H
2
O.
Occurrence:
A rare late-stage, low-temperature hydrothermal mineral in an alkalic pegmatite
dike associated with an intrusive alkalic gabbro-syenite complex.
Association:
Thomasclarkite-(Y), horv´
athite-(Y), donnayite-(Y), petersenite-(Ce),
rhodochrosite.
Distribution:
From Mont Saint-Hilaire, Quebec, Canada.
Name:
To honor Professor Frank Dawson Adams (1859–1942), McGill University, Montreal,
Canada, geologist and petrologist, who studied the Monteregian Hills, of which Mont Saint-Hilaire
is one.
Type Material:
Canadian Museum of Nature, Ottawa, Canada, 82939, 82940.
References:
(1) Grice, J.D., R.A. Gault, A.C. Roberts, and M.A. Cooper (2000) Adamsite-(Y),
a new sodium-yttrium carbonate mineral species from Mont Saint-Hilaire, Quebec. Can. Mineral.,
38, 1457–1466. (2) (2001) Amer. Mineral., 86, 1112 (abs. ref. 1).
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