Jadeite

Formula : NaAl(SiO3)2

Family: 
Pyroxenes
Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c
Dana class: 
65.1.3c.1 (65) Inosilicate Single-Width Unbranched Chains, W=1 (65.1) with chains P=2 (65.1.3c)C2/c clinopyroxenes (Na clinopyroxenes)
High temperature: 
The stability of this mineral is this mineral is limited to high temperature and high pressures :above 5 kbar at 400C (Albite => Jadeite+Quartz) and this reaction ispressure dependant.
Geological context: 
In high-pressure metamorphic rocks of the glaucophane facies; a component of eclogitic rocks.

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
202.139 60.400 (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. -2850656 (Ref.: Internal calculation) -3029300 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. 133.500 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. 159.92 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 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.
185.56 72.36 -41.97 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp.
Reaction properties

Jadeite + 4H+ + 2H2O ⇌ Al+3 + Na+ + 2H4SiO4

298.15 K, 1 bar log10K: 7.56 ΔH°r:-95502 J·mol-1 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp.
T(°C) 0 25 60 100 150 200 250 300
log10K 9.01 7.56 5.75 4.04 2.33 0.92 -0.33 -1.53
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1323.750917 -0.181183 82628.985966 470.161224 -4906074.056701