pyrite
Enable an agent to identify pyrite, assess its composition and alteration state, and judge suitable handling, preservation, processing or investigation.
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 pyrite, assess its composition and alteration state, and judge suitable handling, preservation, processing or investigation.
Pyrite is a naturally occurring iron disulfide mineral, FeS₂, with a cubic crystal structure, metallic lustre and typically pale brass-yellow colour.
It can be Choose a minimally damaging sequence of observations and analytical tests to confirm pyrite.; Assess whether a specimen or lot is sufficiently characterized for a proposed experiment or use.; Identify storage and monitoring needs from texture, alteration and exposure history.; Evaluate mineral liberation and impurity evidence before considering beneficiation or chemical processing.; Flag pyrite-bearing material for oxidation and drainage assessment when its exposure conditions warrant investigation..
Distinguishing features
Confirm FeS2 composition together with cubic crystal structure; composition alone cannot distinguish pyrite from its polymorph marcasite.
Use brittle behavior and substantially greater hardness to distinguish pyrite from soft, malleable native gold; destructive tests require specimen suitability.
Combine brass-yellow metallic appearance with a dark streak and hardness assessment; appearance alone is insufficient to distinguish pyrite from chalcopyrite.
Treat cubes, pyritohedra and striated crystal faces as supporting evidence, while allowing massive, granular and framboidal pyrite without visible diagnostic faces.
Distinguish altered pyrite from iron-oxide replacements by confirming whether an unaltered pyrite phase remains beneath the exterior.
Scope
+ Mineral identity, FeS2 composition and distinction from other iron sulfides
+ Crystal structure, habit, grain size and diagnostic physical properties
+ Pyrite abundance, impurities, inclusions and mineral associations
+ Formation context, specimen provenance and processing history
+ Oxidation, deterioration and conditions affecting preservation
+ Suitability for identification, collection, analysis and material processing
- Whole-rock classification and complete ore-deposit models
- Marcasite, chalcopyrite, pyrrhotite and native gold as separate mineral species
- Mining operations and sulfuric-acid production processes
- Finished jewelry, aggregate and other products containing pyrite
- Complete drainage-water chemistry and ecosystem impact models
Characteristics
- Mineral phase identity
- Pyrite confirmed | pyrite suspected | mixed phases | unresolved; analytical method recorded Separates a mineral identification from a visual resemblance or bulk chemical result.
- Composition and substitution
- Fe:S atomic ratio; elemental mass fractions in wt% or mg/kg; method and detection limits Tests consistency with FeS2 and records departures that may affect interpretation or use.
- Pyrite abundance
- Mass % or volume %, explicitly distinguished; sampling basis A pyrite-bearing rock or concentrate is not equivalent to pure pyrite.
- Crystal habit and texture
- Cubic | pyritohedral | octahedral | massive | granular | framboidal | other documented texture Supports identification and helps interpret formation, liberation and exposed surface area.
- Grain size and exposed surface
- Grain-size distribution in µm or mm; specific surface area in m²/g where measured Influences separation behavior, dust generation and oxidation susceptibility.
- Diagnostic physical properties
- Mohs hardness, density in g/cm³, streak and luster observations; test conditions Provides independent evidence against common look-alike minerals.
- Associated phases and impurity location
- Named mineral phases; lattice-bound element | inclusion | coating | separate grain | unresolved Distinguishes pyrite chemistry from contaminants and associated valuable or hazardous constituents.
- Alteration state
- No alteration observed | tarnished | surface deposits | cracking | powdering | extensively replaced; observation date Determines whether identification, specimen integrity and proposed use remain reliable.
- Exposure conditions
- Temperature in °C, relative humidity in %, water-contact duration, oxygen exposure and measured pH where relevant Provides context for interpreting deterioration and planning storage or experiments.
- Material-specific hazard and regulatory identity
- Verified substance identifiers, supplier grade, jurisdiction, dated safety documentation and applicable classification Avoids assigning a universal hazard classification to specimens, powders and mixed concentrates with different compositions.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.pyrite
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 16 findings · 24 questions.
Pyrite identity Establish whether the material contains the pyrite mineral phase.
Brassy appearance and iron-sulfur composition each admit important false identifications.
Phase and composition
Connect chemical evidence with crystal-structure evidence.
FeS2 phase confirmation
Record the basis and confidence for identifying cubic FeS2 rather than another sulfide.
- What chemical and structural evidence establishes pyrite, and does it exclude marcasite or a mixed iron-sulfide assemblage? definition
- Which measurements, reference patterns and sampled locations support the identification? provenance
Look-alike discrimination
Evaluate physical observations without treating appearance as proof.
Diagnostic test selection
Select complementary observations that distinguish pyrite from gold and similar sulfides.
- How do habit, streak, hardness and brittle behavior support or contradict the proposed identification? measurement
- Which tests can resolve the remaining ambiguity without unacceptable damage to the specimen? action
Pyrite material constitution Describe how much pyrite is present and how it occurs within the material.
A crystal, framboidal sediment and mixed concentrate present different analytical and processing problems.
Abundance and associations
Separate the pyrite phase from host material, inclusions and coatings.
Phase proportions and impurities
Record pyrite abundance and the location of constituents relevant to use or hazard.
- What fraction of the specimen or lot is pyrite, and how representative is the analyzed sample? measurement
- Are detected trace elements incorporated in pyrite, held in inclusions or carried by separate associated minerals? boundary
Texture and origin
Connect morphology and grain relationships to documented origin and treatment.
Grain history
Record texture and provenance that affect sampling, interpretation and mineral liberation.
- What grain sizes, crystal forms, intergrowths and fractures characterize the pyrite? measurement
- What locality, host material, formation interpretation and crushing or chemical-treatment history are documented? provenance
Pyrite alteration and preservation Assess existing deterioration and the conditions that may sustain it.
Oxidation can change pyrite-bearing material, damage specimens and generate acidic reaction products.
Alteration evidence
Distinguish observed symptoms from confirmed reaction products.
Remaining pyrite and products
Track changes in the original mineral and identify secondary material where possible.
- What tarnish, deposits, cracking or powdering is present, and which secondary phases have been analytically identified? measurement
- Does the object retain pyrite, or is it principally a replacement preserving an earlier pyrite form? boundary
Exposure and intervention
Relate alteration to storage, water contact and proposed treatment.
Preservation decision
Choose monitoring or intervention using specimen-specific evidence.
- What humidity, temperature, oxygen and water-contact history accompanies the observed changes? provenance
- What storage adjustment, isolation or conservation treatment is supported for this specimen, and how will its effectiveness be checked? action
Pyrite use and handling Determine whether the characterized material is suitable for a specific activity.
Pyrite identity alone does not establish processing suitability, dust controls or environmental behavior.
Fitness for intended use
Connect grade, texture and stability to the proposed use.
Acceptance and processing
Record requirements for collection, analysis, beneficiation or reaction studies.
- What pyrite abundance, impurity limits, grain size and alteration state does the intended use require? boundary
- What additional characterization or preparation is necessary before accepting this material for that use? action
Dust and reactive release
Assess hazards associated with the actual material and proposed operation.
Operation-specific controls
Tie handling decisions to physical form, impurities, reaction conditions and applicable documentation.
- What dust, heating or oxidation hazards are supported by the lot composition, planned operation and current safety documentation? provenance
- What controls and tests are needed to manage particulate exposure or evaluate acidic and metal-bearing releases? 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.
- The listed kinds are crystal habits and aggregate textures, not separate mineral species.
- Values describe typical pyrite or ideal FeS₂; impurities, inclusions and porosity can change specimen measurements.
- Chemical registry identifiers, regulatory classifications and exposure limits require verification for the particular material; none are asserted here.
- Which of these check these first hold for the sense of pyrite this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Cubic crystals
- Pyritohedral crystals
- Octahedral crystals
- Framboidal pyrite
- Massive pyrite
- Which of these kinds and varieties hold for the sense of pyrite this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Chemical formula - FeS₂ - Composition alone does not distinguish pyrite from its polymorph marcasite.
- Which of these identifiers and schemes hold for the sense of pyrite this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Historical and some continuing use as a sulfur source for sulfuric acid production.
- Mineral specimens and decorative objects.
- Jewellery, including material commercially described as marcasite.
- Geological investigation of mineral deposits and sedimentary formation conditions.
- Processing of gold-bearing pyrite where gold occurs as inclusions or within the mineral.
- Which of these real-world use hold for the sense of pyrite this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Mohs hardness - 6-6.5 - Mohs scale
- Density - 4.9-5.2 - g/cm³
- Iron mass fraction in ideal FeS₂ - Approximately 46.5 - %
- Sulfur mass fraction in ideal FeS₂ - Approximately 53.5 - %
- Which of these typical measurements hold for the sense of pyrite 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.
- Oxidation in the presence of water and oxygen can generate acidity, contributing to acid mine drainage.
- Pyrite-bearing aggregate or fill can deteriorate through oxidation and subsequent expansive mineral formation.
- Susceptible specimens can crumble and develop acidic alteration products during storage.
- Oxidation of finely divided pyrite can release heat and contribute to self-heating in sulfide-bearing materials.
- Roasting or burning pyrite can release sulfur dioxide.
- Which of these failure modes and hazards hold for the sense of pyrite this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Trace-element content, associated minerals and commercial value vary by deposit.
- Local climate, drainage and exposure conditions affect weathering and acid-generation behaviour.
- Which of these regional variation hold for the sense of pyrite 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.
- Marcasite - Also FeS₂, but orthorhombic rather than cubic; crystallographic testing separates them reliably.
- Gold - Gold is much denser, softer and malleable; pyrite is hard and brittle and typically leaves a dark streak.
- Chalcopyrite - Chalcopyrite is CuFeS₂ and is substantially softer, typically about 3.5-4 on the Mohs scale.
- Pyrrhotite - Pyrrhotite has variable composition near Fe₁₋ₓS and is commonly magnetic, unlike ordinary pyrite.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of pyrite this model covers, and on what evidence? provenance
What the second pass must settle
- Which authoritative mineralogical references and analytical criteria should define the minimum evidence for confirmed pyrite identity?
- Which substance identifiers and jurisdiction-specific classifications apply to natural pyrite, synthetic FeS2 and commercial mixed concentrates?
- What preservation conditions and interventions are supported for different pyrite textures and existing alteration states?
- Which measured thermal transformations should be recorded for pyrite under specified atmospheres and pressures, instead of assuming conventional melting and boiling points?
- Which tests best establish oxidation and acid-generation behavior for a given pyrite-bearing material while accounting for associated minerals and neutralizing capacity?