Convert oxide data into moles and cation ratios. Normalize totals, review indices, and export reports. Make mineral chemistry checks faster and more reliable.
This sample resembles a basaltic oxide report. Use “Load example data” to copy it into the form.
| Oxide | Wt% |
|---|---|
| SiO2 | 49.50 |
| TiO2 | 1.20 |
| Al2O3 | 15.60 |
| FeO | 9.00 |
| Fe2O3 | 2.50 |
| MnO | 0.15 |
| MgO | 7.50 |
| CaO | 11.00 |
| Na2O | 3.20 |
| K2O | 0.80 |
| P2O5 | 0.25 |
| H2O | 0.30 |
| Total | 101.00 |
Note: Mg# here uses FeO as Fe2+ only. For detailed redox partitioning, use a dedicated speciation workflow.
Oxide weight percent is the starting point for mineral chemistry and petrography workflows. This calculator accepts common oxides, converts each wt% into grams for the chosen sample mass, and keeps the math transparent. A 100 g mass is practical because wt% equals grams, but any mass works when you must match a weighed powder split. Negative entries are blocked to protect totals and prevent accidental sign errors. Units stay consistent for cross-checks.
Molar-mass conversion turns grams into moles, enabling mol% comparisons between samples. Mol% often highlights subtle shifts in components that look small in wt%, especially TiO2, MnO, or P2O5. The table reports moles of each oxide, then computes mol% as 100 × moles(oxide) divided by total moles(oxide). This view helps flag accessory-phase control, such as apatite enrichment or ilmenite saturation, across replicate analyses. It also supports side-by-side trend tracking.
Oxygen-basis normalization is the core step for building cation proportions that resemble mineral formulas. The tool calculates total moles of oxygen from all oxides, then scales cations to a fixed oxygen basis such as 4, 6, 8, 12, or 24. Selecting a matching basis aligns results with common stoichiometries, improves comparison between runs, and avoids mixing incompatible formula units when screening data from different instruments or labs. This reduces confusion in reviews.
Oxide-total normalization rescales compositions when the measured sum is not near 100%. When enabled, every oxide is multiplied by the same factor, 100 divided by the input total, preserving relative proportions while improving comparability. This is useful when volatiles are underestimated, when minor oxides were not reported, or when Fe is split between FeO and Fe2O3. The warning banner highlights totals outside typical quality-control ranges. You can document the scale factor for traceability.
Fast quality indicators support interpretation before detailed modeling. The calculator reports total alkalis as Na2O + K2O, a key variable in many classification diagrams, and an approximate Mg# based on molar Mg and Fe2+ from FeO. Higher Mg# typically tracks more magnesian, less evolved compositions, while higher alkalis can indicate differentiation or feldspathic input. Exported CSV and PDF tables make reviews, audits, and reporting consistent across teams.
It rescales cation totals to a fixed number of oxygens (for example 6 or 8). This makes outputs comparable to standard mineral formula units and reduces scaling differences between samples.
Normalize when totals are meaningfully off due to missing components, analytical drift, or reporting differences. If you are auditing raw lab output, keep normalization off and interpret the warning message.
Many datasets report iron as FeO, Fe2O3, or both. Keeping them separate preserves the original reporting style. The table still converts each oxide to moles, oxygen, and cations consistently.
Mg# is computed as 100 × molar Mg / (molar Mg + molar Fe2+), using FeO as the Fe2+ source. It is a quick screening metric, not a full redox speciation model.
Mol% emphasizes changes in oxide mole proportions. Minor oxides can look small in wt% but shift mol% enough to suggest accessory minerals, fractionation trends, or mixing between endmembers.
Exports capture the visible tables: oxide wt%, grams, moles, mol%, and oxygen-basis cations for results, plus the session history table when available. This supports reporting and reproducible reviews.
Stored locally in your session (up to 50 rows).
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.