Staurolite

Formula : Fe2Al9Si4O23(OH)

Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
Dana class: 
52.2.3.1 (52) Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O (52.2) with cations in [4] and >[4] coordination (52.2.3) Dana Group
High temperature: 
Its stability ranges from 500 to 700C and depends on the chemistry of rocks, on pressure and on fugacity of the water.
Geological context: 
Common in pelitic schists, gneisses, and argillaceous rocks regionally metamorphosed to amphibolite grade.

Dernière mise à jour le 25.01.2021

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
 V°
cm3·mol-1
 ΔGºf
J·mol-1
 ΔHºf
J·mol-1
 Sº
J·mol-1·k-1
 CP
J·mol-1·K-1
851.863 224.400 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp. -10469141 (Ref.: Internal calculation) -11191200 (Ref.: 87woo/gar) Woods T. L. and Garrels R. M. (1987) Thermodynamic values at low temperature for natural inorganic materials. An uncritical summary. Oxford University Press, New York. 489.946 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp. 643.35 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp.
CP(T) = a + b·T + ·c·T-2 (T in Kelvin)
a
J·mol-1·K-1
 b * 103
J·mol-1·K-2
 c * 10-5
J·K·mol-1
 Maier Kelley Ref.
866.59 154.56 -239.41 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp.
Reaction properties

Staurolite + 31H+ ⇌ 9Al+3 + 2Fe+2 + 4H4SiO4 + 8H2O

298.15 K, 1 bar log10K: 216.34 ΔH°r:-1956484 J·mol-1 (Ref.: 87woo/gar) Woods T. L. and Garrels R. M. (1987) Thermodynamic values at low temperature for natural inorganic materials. An uncritical summary. Oxford University Press, New York.
T(°C) 0 25 60 100 150 200 250 300
log10K 247.44 216.34 180.10 146.64 113.13 85.81 62.48 41.59
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-6529.733445 -1.006143 452251.228444 2328.129494 -20588442.365910