olivine
Enable an AI agent to identify olivine, assess its composition and alteration, and select justified tests, handling or uses for a particular grain, specimen or material lot.
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.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to identify olivine, assess its composition and alteration, and select justified tests, handling or uses for a particular grain, specimen or material lot.
Olivine is a nesosilicate mineral series of magnesium-iron orthosilicates, (Mg,Fe)2SiO4, that crystallizes in the orthorhombic system as a complete solid solution between forsterite (Mg2SiO4) and fayalite (Fe2SiO4) and is the dominant silicate of Earth's upper mantle.
It can be Select microscopy, phase analysis and chemical measurements to resolve an uncertain olivine identification.; Map grain compositions and separate homogeneous material from zoned or mixed populations.; Estimate surviving olivine and identify alteration or inclusions that affect a proposed use.; Choose representative subsamples and evaluate whether crushing, separation or polishing will answer the intended question.; Compare a characterised lot with explicit requirements for gem, refractory, foundry or experimental use.; Design a bounded reaction test and assess its results before extrapolating to weathering or carbonation performance..
Distinguishing features
Require agreement between phase identification and chemistry consistent with the forsterite-fayalite series; green colour alone is insufficient. Reference: [Handbook of Mineralogy: Forsterite](https://www.handbookofmineralogy.org/pdfs/forsterite.pdf).
Check whether observed fracture and cleavage fit olivine: forsterite has imperfect cleavage and conchoidal fracture, useful supporting observations when separating it from conspicuously cleaved minerals. Reference: [Handbook of Mineralogy: Forsterite](https://www.handbookofmineralogy.org/pdfs/forsterite.pdf).
Distinguish olivine from compositionally related high-pressure phases by crystal-structure evidence; composition alone cannot separate forsterite from wadsleyite or ringwoodite. Reference: [Handbook of Mineralogy: Forsterite](https://www.handbookofmineralogy.org/pdfs/forsterite.pdf).
Identify olivine at the mineral-phase level before applying its name to a rock or processed lot; record how much of the examined material is actually that phase.
For a grain preserving an apparent olivine shape, test its interior and rim separately before deciding whether it remains olivine or is substantially replaced.
Scope
+ Evidence that an observed mineral phase is olivine
+ Magnesium-iron composition, minor constituents and zoning within olivine
+ Grain size, fractures, inclusions and exposed surfaces
+ Alteration, replacement and experimentally observed reactivity
+ Suitability of a specified olivine specimen or lot for a proposed operation
- Classification and bulk properties of host rocks such as dunite, peridotite and basalt
- Whole-deposit resource estimates and mining operations
- Independent models of alteration products and associated minerals
- Gemstone valuation, jewellery design and commercial grading systems
- Plant design and project-level carbon-removal accounting
Characteristics
- Phase identification
- confirmed olivine; probable olivine; mixed phases; unresolved; rejected identification Controls whether olivine-specific interpretations and actions are warranted.
- Forsterite component
- Fo mol%, using 100 × Mg/(Mg + Fe2+) on a molar basis; record analytical method and iron-valence assumptions Locates the analysed olivine within the magnesium-iron series without confusing grain chemistry with bulk-rock chemistry.
- Compositional zoning
- Spatially located Fo mol% and constituent concentrations across core, rim and intermediate zones Shows whether a single composition adequately represents the grain.
- Minor and trace constituents
- Element or oxide mass fraction in wt% or mg/kg, with detection limits and analysed phase Supports classification and use assessment while distinguishing lattice constituents from inclusions or contamination.
- Olivine abundance
- Mass% or volume%, explicitly distinguished, with sampling and quantification method Prevents properties of an olivine-bearing mixture from being attributed to pure olivine.
- Grain and particle dimensions
- µm or mm; distinguish mineral grains from processed particles and state distribution basis Informs sampling, liberation, surface exposure and processing choices.
- Fracture and inclusion condition
- Observed fracture distribution, inclusion identity and location, and imaging resolution Constrains cutting, testing and interpretation of whole-specimen measurements.
- Alteration extent
- Estimated replaced area% or volume%, with identified products, method and uncertainty Separates surviving olivine from material that has acquired different mineral properties.
- Host and origin
- Links to host specimen, sampling locality, meteorite or synthesis batch, with evidence Preserves context needed to interpret composition and assess representativeness.
- Measured reaction response
- Dissolution rate, released constituents or phase conversion, with units, duration and experimental conditions Supports use decisions from observed behaviour rather than mineral identity alone.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.olivine
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 9 findings · 18 questions.
Olivine identity Establish which mineral phase the name denotes and how confidently it has been recognised.
Olivine can label a mineral series, a broader group or a commercial mixture; these meanings support different decisions.
Name and phase boundary
Connect the registry term to the actual material being described.
Intended olivine meaning
Record whether the claim concerns an Mg-Fe olivine phase, broader group membership or an olivine-bearing product.
- Does olivine here mean the forsterite-fayalite series, the broader mineral group or a supplier's material designation? definition
- Which observations belong to the olivine phase, and which describe the host rock or mixed lot? boundary
Diagnostic evidence
Assess converging evidence and unresolved alternatives.
Phase identification confidence
Retain the observations, reference matches and limitations supporting an olivine identification.
- Which microscopy, Raman or diffraction results support olivine, and which reference material or pattern was used? measurement
- What additional test would distinguish the remaining alternatives, including replacement minerals or compositionally similar phases? action
Composition and context Describe the analysed olivine composition and the material population it represents.
A bulk assay or one grain measurement cannot automatically represent every olivine grain in a specimen or lot.
Solid-solution composition
Locate individual analyses within the Mg-Fe series and document departures from a simple end-member mixture.
Fo content and substitutions
Record composition calculations together with analytical limitations and spatial variation.
- What Fo mol% follows from the measured cation proportions, and how was ferrous iron distinguished or assumed? measurement
- Do core-rim profiles or minor-element analyses show variation large enough that one reported composition is misleading? measurement
Sample representativeness
Relate analysed grains to their host, collection point and processed material.
Olivine population origin
Document which grain population was sampled and whether preparation selected particular compositions or conditions.
- Which host specimen, locality or synthesis batch supplied these grains, and what supports that attribution? provenance
- Did picking, crushing or separation preferentially retain particular grain sizes, compositions or alteration states? boundary
Grain integrity and alteration Assess surviving olivine, internal defects and secondary material.
A specimen's external appearance can conceal fractures, inclusions and replacement that change its behaviour.
Grain architecture
Describe dimensions, boundaries and internal discontinuities at the scale relevant to an operation.
Fractures, inclusions and liberation
Determine whether the material consists of intact olivine grains, fractured grains or composite particles.
- What are the olivine grain sizes, fracture distribution and inclusion identities at the available imaging resolution? measurement
- Would the proposed crushing, cutting or polishing expose inclusions, separate olivine from its host or destroy needed textures? action
Replacement and surfaces
Separate fresh olivine from altered rims, coatings and replaced interiors.
Surviving olivine fraction
Quantify remaining olivine and distinguish identified secondary phases from visually inferred alteration.
- Which phases occupy rims, fractures and interiors, and what fraction of the examined material remains olivine? measurement
- Does the evidence justify treating this object as olivine, altered olivine or a replacement aggregate linked to former olivine? boundary
Olivine use and reaction Connect measured mineral properties to a specified operation and its acceptance evidence.
Olivine identity alone does not establish gem quality, industrial suitability or reaction performance.
Operation-specific suitability
Evaluate the particular specimen or lot against the requirements of its intended use.
Use requirements and limits
Record the properties that control acceptance for the proposed gem, thermal, granular or analytical application.
- For the intended use, what limits apply to composition, olivine abundance, grain size, fractures, inclusions or alteration? action
- Which measured properties establish acceptance, and which missing tests prevent a decision for this specimen or lot? measurement
Reaction performance
Characterise olivine response under recorded chemical and thermal conditions.
Conditioned reaction evidence
Keep observed dissolution, conversion and constituent release tied to the tested composition and environment.
- Under what temperature, pH, fluid composition, gas exposure, surface-area basis and duration was olivine reaction measured? measurement
- What evidence distinguishes olivine dissolution from actual carbonate formation, secondary-phase formation or release of minor constituents? measurement
- What further test is needed before applying the observed response to a different particle size, fluid regime or operating scale? 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.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- forsterite (Fo, Mg2SiO4 end-member)
- fayalite (Fa, Fe2SiO4 end-member)
- magnesian olivine / chrysolite (intermediate Fo-rich compositions, the common mantle and basaltic olivine)
- hortonolite (intermediate Fe-Mg olivine, historically named)
- tephroite (Mn2SiO4, manganese olivine end-member of a related series)
- gem peridot (transparent green gem-quality olivine, typically Fo-rich)
- dunite / olivine sand (rock- and sediment-scale occurrences of nearly monomineralic olivine)
- synthetic / industrial olivine (foundry, refractory, and slag-conditioning grades)
- Which of these kinds and varieties hold for the sense of olivine this model covers, and on what evidence? provenance
Sources
- Olivine: Mineral information, data and localities - IMA-group status, formula (Mg,Fe)2SiO4, orthorhombic Pbnm, hardness, density range, and distinction from olivine-group members such as tephroite.
What the second pass must settle
- Does vr.tr.olivine intend only the forsterite-fayalite series or all members of the olivine mineral group?
- Does an existing Vercy world model already own this concept, requiring a registry link instead of a separate publication?
- Which identification methods and confidence criteria are sufficient for field, laboratory and commercial-lot decisions respectively?
- What sampling and alteration thresholds justify representing a heterogeneous lot with one olivine composition and condition?
- Which application-specific acceptance criteria and reaction evidence are required before recommending thermal use, gem processing or weathering and carbonation trials?