Spinel Volume Calculator

xMELTS is the next generation MELTS model, being developed as part of an ongoing collaboration. Get advanced online access here to new solid solution models that will be included in xMELTS.

MAGMA logo: a volcano with a fire fountain based on the Caltech logo


Please log in before filling out the form!

General options

 Input oxide components, equilibrium conditions (optional) and P-T

MgO FeO Fe2O3 Al2O3 Cr2O3 TiO2
Wt % oxides:

 Input end-member proportions, equilibrium conditions (optional) and P-T

FeCr2O4 FeAl2O4 Fe3O4 Fe2TiO4
Mole fraction: use independent
MELTS end members
MgCr2O4 MgAl2O4 MgFe2O4 Mg2TiO4

 Input site fractions and P-T conditions

Mg2+ Fe2+ Fe3+ Al3+ Cr3+ Ti4+
Tetrahedral site fraction: N/A N/A
Octahedral site fraction:

 Input MELTS-type variables and P-T conditions

XMgAl2O4 XFeCr2O4 XFe2TiO4 XFe3O4
r0:   r1:   r2:   r3:
[4]XMg2+−2[6]XMg2+ ½(2[6]XAl3+[4]XAl3+) ½(2[6]XFe3+[4]XFe3+)
s0:   s1:   s2:

Ordering state options

 Use input site fractions or MELTS variables

 Assume normal ordering i.e. [4]A[6]B2O4

 Assume inverse ordering within range of configurational freedom e.g. [4]B[6](A,B)2O4

 Use MELTS ordering model (for Ts ≥ 500 °C)

Temperature (Ts) in °C: same as Tv
Pressure (Ps) in bars: same as Pv

Volume options

Temperature (Tv) in °C:
Pressure (Pv) in bars: