Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

MgO

MgO weight percent.

FeO

FeO weight percent.

Fe2O3

Fe2O3 weight percent.

SiO2

SiO2 weight percent.

Compute the molar Mg number (100*Mg/(Mg+Fe)) with ferric iron converted to ferrous, paired with SiO2 for differentiation-trend plots. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Mg number

Molar Mg number between 0 and 100.

FeO total

Total iron as FeO weight percent.

SiO2

SiO2 weight percent.

• Classification diagrams and geochemical ratios require appropriate normalization, oxidation-state treatment, volatile basis, analytical quality, alteration screening, mineral or whole-rock context, and a composition within the method's calibration domain.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• AFM Diagram Calculator

  Convert whole-rock oxides to AFM coordinates with ferric iron recalculated to FeO for the tholeiitic-calc-alkaline AFM triangle.

• Activity Number Calculator

  Compute the Skempton activity A as plasticity index divided by the clay fraction finer than two micrometers, both in percent.

• Degree Of Consolidation Calculator

  Average degree of consolidation U inverted from the Terzaghi relations: Tv = (pi/4)*(U/100)^2 for U <= 60 percent and Tv = 1.781 - 0.933*log10(100 - U) for U > 60 percent.