magnetite
Enable an agent to identify magnetite, assess the condition and suitability of a particular specimen or batch, and determine which handling, processing or use decisions its evidence supports.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to identify magnetite, assess the condition and suitability of a particular specimen or batch, and determine which handling, processing or use decisions its evidence supports.
Magnetite is a ferrimagnetic iron oxide mineral with ideal composition Fe₃O₄, containing both Fe(II) and Fe(III) in an inverse-spinel crystal structure.
It can be Select complementary measurements to confirm magnetite and resolve competing iron oxide identifications.; Compare specimens or batches against explicit purity, particle-size and magnetic-performance requirements.; Assess whether magnetic separation is supported by measured response and the surrounding material.; Track oxidation or other alteration and determine when identity or performance needs reassessment.; Specify handling and storage from the actual particle form, impurities, coating and applicable safety documentation.; Qualify a batch for a defined use while identifying missing evidence that prevents acceptance..
Distinguishing features
Confirm a magnetite-compatible crystal phase using diffraction or complementary structural evidence; black colour and attraction to a magnet alone are insufficient.
Establish evidence consistent with mixed Fe(II)/Fe(III) iron oxide composition; ideal magnetite differs from the all-ferric composition of hematite and maghemite.
Distinguish magnetite from maghemite using oxidation-state or other complementary evidence when their related structures make a single phase-identification method inconclusive.
Distinguish magnetite from metallic iron or magnetic sulfides through elemental composition and phase identification.
Treat lodestone as naturally remanently magnetized magnetite-bearing material; do not require every magnetite specimen to behave as a permanent magnet.
Scope
+ Magnetite phase identity, composition, impurities and distinction from related iron oxides
+ Crystal structure, phase proportions and departures from ideal stoichiometry
+ Magnetic properties tied to temperature, particle size and measurement history
+ Natural specimen and synthetic batch properties, including particle form and surface condition
+ Oxidation, dissolution, handling constraints and evidence of suitability for a specified use
- Whole ore deposits, host rocks and mining operations containing magnetite
- Other iron oxide phases except as alternatives, impurities or alteration products
- Manufacturing processes and equipment that produce or separate magnetite
- Finished products such as ferrofluids, coatings and medical formulations
- Organisms containing biogenic magnetite and their biological functions
- Regulatory approval or safety assessment of a complete product containing magnetite
Characteristics
- Phase identity and supporting evidence
- Confirmed magnetite | probable magnetite | mixed iron oxide | unresolved; record analytical method Prevents appearance or magnetic attraction from becoming the sole identification criterion.
- Magnetite phase fraction
- Mass % or volume %, with method, uncertainty and reporting basis Separates a magnetite phase from a rock, powder or product that merely contains it.
- Iron oxidation-state balance
- Fe(II)/total Fe molar fraction; ideal Fe3O4 corresponds to 1/3 Helps assess identity, nonstoichiometry and oxidation, provided other iron-bearing phases are accounted for.
- Substitution and impurity profile
- Elemental mass % or mg/kg, distinguishing lattice substitution from separate phases Explains differences in magnetic behaviour, processing performance and acceptable grade.
- Particle and crystallite dimensions
- Particle-size distribution in nm or µm; crystallite size reported separately Particle, crystallite and aggregate sizes can govern different magnetic, surface and handling behaviours.
- Specific surface area
- m²/g, with measurement and preparation method Supports comparison of surface reactivity and adsorption performance.
- Magnetic response
- Magnetization in A·m²/kg, coercivity in A/m and remanence in A·m²/kg, with temperature and field protocol Determines whether the material meets a magnetic separation or other magnetic-performance requirement.
- Magnetic regime
- Domain or relaxation regime established by measurement; temperature and observation timescale required Avoids assigning bulk magnetic behaviour automatically to fine particles.
- Surface and alteration condition
- Characterized surface composition, oxidation products, coating and evidence date A magnetite core can coexist with a surface that controls reactions and dispersion differently.
- Material form and grade
- Natural specimen | ore concentrate | synthetic powder | coated particles | dispersion; supplier or application grade Connects evidence and constraints to the actual material being handled.
- Material identity documentation
- Links to verified chemical identifiers, batch certificate, safety data sheet and applicable jurisdiction Keeps substance identity distinct from the classification and documentation of a particular supplied form.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Phase and composition Establish whether the material is magnetite and what compositional qualifications apply.
Magnetism alone does not establish magnetite identity, and mixed or substituted materials need explicit boundaries.
Phase identification
Connect the magnetite assignment to structural and chemical evidence.
Magnetite assignment
Record the evidence supporting magnetite and the alternatives that remain unresolved.
- Which measurements support a magnetite phase assignment for this specimen or batch? measurement
- What evidence distinguishes it from maghemite, hematite, metallic iron or magnetic sulfides? boundary
Composition and mixtures
Separate ideal phase composition, lattice substitutions and accompanying phases.
Composition basis
Require a clear basis for purity and oxidation-state claims.
- What magnetite fraction and Fe(II)/total Fe fraction were measured, with what uncertainty? measurement
- Which detected elements occupy the magnetite structure, and which belong to separate phases or surface material? boundary
Particle and surface form Describe the physical scale and exposed interfaces of the actual magnetite material.
Bulk specimens, fine powders and coated nanoparticles cannot share an unqualified set of material properties.
Size and aggregation
Distinguish crystallites, particles and aggregates.
Measured size population
Tie each reported size to the population and method it describes.
- Does the reported size describe crystallites, primary particles, aggregates or hydrodynamic diameter? definition
- What size distribution and morphology were measured, and how was the sample dispersed or prepared? measurement
Surface identity
Record coatings and surface composition separately from the underlying phase.
Accessible magnetite surface
Determine whether the exposed interface represents magnetite, an alteration layer or an added coating.
- What evidence identifies the surface composition, coating coverage and specific surface area? measurement
- Which observed properties belong to the magnetite core, and which belong to a coating or dispersion medium? boundary
Magnetic behaviour Represent magnetic response under stated measurement and operating conditions.
Magnetite identification does not by itself establish useful magnetization, remanence or particle-scale behaviour.
Field response
Capture comparable magnetic measurements and their normalization.
Magnetization evidence
Attach magnetic-performance claims to a defined sample and field protocol.
- What magnetization, coercivity and remanence were measured at the stated temperature and applied-field range? measurement
- Are mass-normalized values based on the whole sample or its magnetite fraction, and how was that basis established? definition
Temperature and history
Connect magnetic state to thermal conditions, particle scale and prior treatment.
Conditional magnetic state
Record evidence for magnetic regimes and transitions without assuming ideal bulk behaviour.
- What measurements establish domain behaviour or superparamagnetic relaxation at the relevant temperature and observation timescale? measurement
- What thermal and magnetic history preceded measurement, and were Verwey or Curie transition features investigated? provenance
Alteration and stability Track changes that affect magnetite identity, surface chemistry and performance.
A historical magnetite identification may cease to describe material altered during storage, heating or chemical exposure.
Oxidation and phase change
Relate environmental and thermal exposure to observed alteration.
Alteration evidence
Distinguish demonstrated phase changes from changes inferred only from appearance or magnetism.
- What oxygen exposure, temperature, humidity and storage duration has the material experienced? provenance
- Do repeat measurements show changes in magnetite fraction, iron oxidation state or formation of other iron oxide phases? measurement
Chemical exposure
Describe dissolution and surface reactions in a specified surrounding medium.
Medium-dependent reactivity
Bound stability claims by the solution chemistry and exposure conditions tested.
- Under what pH, redox conditions, ligands, temperature and exposure duration was dissolution or iron release measured? measurement
- What observed change requires recharacterization before the material can continue in its intended use? action
Grade, use and handling Connect documented material properties to a defined application and supplied form.
Mineral identity alone cannot establish application suitability or the handling requirements of a particular batch.
Application qualification
Assess a magnetite batch against explicit use requirements.
Fitness for specified use
Require measurable acceptance criteria for the proposed operation.
- Which limits on phase purity, contaminants, size distribution, density or magnetic response govern the proposed use? action
- Which batch measurements demonstrate compliance, and which requirements remain untested? measurement
Traceability and exposure
Associate identity and handling evidence with the actual specimen or supplied batch.
Form-specific documentation
Separate magnetite substance records from impurity-, particle- and formulation-dependent requirements.
- Which verified chemical identifiers, origin records and safety documents apply to this exact material form and batch? provenance
- What handling controls and exposure limits apply in the relevant jurisdiction given its dustiness, particle size, impurities and dispersion medium? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This description is recalled knowledge, not source-verified research.
- Physical values describe approximately pure bulk material; substitutions, oxidation, defects, and nanoscale dimensions can alter them.
- Verify grade-specific identifiers, hazard classification, exposure limits, and applicable regulations for the actual supplied material.
- Which of these check these first hold for the sense of magnetite this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Lodestone: naturally magnetized magnetite with appreciable permanent magnetization
- Titaniferous magnetite: titanium-bearing magnetite within the magnetite-ulvöspinel solid-solution series
- Which of these kinds and varieties hold for the sense of magnetite this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- CAS Registry Number - 1309-38-2 - Identifies iron(II,III) oxide; natural mineral samples may contain substitutions, impurities, or associated minerals.
- Chemical formula - Fe₃O₄ - Ideal composition, also expressed as Fe²⁺Fe³⁺₂O₄; a formula does not establish sample purity.
- Which of these identifiers and schemes hold for the sense of magnetite this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Major iron ore used as feedstock for iron and steel production
- Dense-medium separation, including coal preparation
- Black pigment in coatings and other formulated materials
- Magnetic particles for separation and recovery processes
- Recording geological magnetic information in paleomagnetic studies
- Which of these real-world use hold for the sense of magnetite this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Density of relatively pure crystalline magnetite - Approximately 5.2 - g/cm³
- Mohs hardness - 5.5-6.5 - Mohs scale
- Curie temperature of near-stoichiometric magnetite - Approximately 580 - °C
- Iron mass fraction in ideal Fe₃O₄ - Approximately 72.4 - % by mass
- Which of these typical measurements hold for the sense of magnetite this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Airborne fine dust presents an inhalation exposure concern; assessment depends on particle size and associated contaminants.
- Oxidation to maghemite or hematite changes composition and magnetic properties.
- Titanium substitution, other impurities, and grain size can substantially change magnetic behavior and processing performance.
- Heating above the Curie temperature removes ferrimagnetic order while the material remains above that temperature.
- Agglomeration of fine particles can impair dispersion, separation efficiency, and reproducibility.
- Which of these failure modes and hazards hold for the sense of magnetite this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Deposit geology controls associated minerals, substitution chemistry, and the beneficiation needed to produce a usable concentrate.
- Chemical registration and workplace dust requirements depend on jurisdiction and supplied form; mineral identity alone does not establish compliance.
- Which of these regional variation hold for the sense of magnetite this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Hematite - Hematite is α-Fe₂O₃, with a different crystal structure and generally much weaker magnetic response than magnetite.
- Maghemite - Maghemite is γ-Fe₂O₃, a ferrimagnetic, vacancy-bearing spinel-related oxide containing ferric iron rather than magnetite's mixed Fe(II)/Fe(III).
- Wüstite - Wüstite is a nonstoichiometric, predominantly Fe(II) oxide commonly written Fe₁₋ₓO, with a rock-salt structure.
- Lodestone - Lodestone is magnetite distinguished by appreciable natural permanent magnetization, rather than a separate mineral species.
- Magnetite ore - Ore is a geological material containing economically recoverable magnetite alongside other constituents; it is not necessarily pure Fe₃O₄.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of magnetite this model covers, and on what evidence? provenance
What the second pass must settle
- Which authoritative identifiers and naming conventions best cover natural magnetite, synthetic Fe3O4 and substituted magnetite without conflating mixtures or neighbouring phases?
- What minimum complementary analytical evidence should establish magnetite rather than maghemite in fine, partially oxidized or poorly crystalline material?
- Which reference values and condition-dependent ranges for density, magnetic transitions and thermal behaviour are sufficiently supported to include, and when do transformation or decomposition make melting or boiling fields inappropriate?
- Which jurisdiction-specific hazard classifications and exposure limits apply to each supplied form, particularly respirable powders, nanoparticles and impurity-bearing concentrates?
- What application-specific acceptance criteria and alteration thresholds should trigger rejection, restricted use or recharacterization of a magnetite batch?