rock
material consisting of the aggregate of minerals like those making up the Earth's crust
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 recognise rock as a geological material, assess its composition and condition, and judge its suitability for a proposed use.
Rock is a naturally occurring solid geological material composed of an aggregate of minerals, mineraloids, or both, forming part of the Earth's crust and underlying solid interior.
It can be Identify and classify a specimen using field observations, petrography and appropriate analytical evidence.; Select representative samples across visible compositional, fabric and weathering variations.; Compare measured properties with the requirements of a specified aggregate, dimension-stone or engineering use.; Assess likely splitting directions and processing constraints from bedding, foliation, grain structure and fractures.; Select further tests when moisture, alteration, pore structure or constituent hazards could change a decision.; Route an identified subtype to its specialised model while retaining shared composition and condition records..
Distinguishing features
Assess whether the material is a geological aggregate rather than an individual mineral crystal; a rock need not contain several mineral species.
Record texture, constituent relationships and geological context to distinguish rock from manufactured materials such as concrete or ceramic.
Test whether cohesion and fabric support classification as rock rather than loose sediment, explicitly recording weakly consolidated boundary cases.
Treat a specimen, boulder or outcrop as an occurrence of rock material rather than allowing its shape or location to define the material kind.
Use metamorphic rock as a narrower classification when supported by evidence, retaining this model for shared rock properties.
Scope
+ Mineral composition, accessory constituents and compositional variability
+ Grain size, texture, cementation, bedding, foliation and other material fabrics
+ Broad geological formation class and evidence supporting identification
+ Physical and mechanical properties under recorded test conditions
+ Weathering, alteration, fractures and their effects on material condition
+ Material suitability and constituent-dependent hazards for specified activities
- Individual mineral species and their complete crystallographic models
- Detailed metamorphic processes and classifications owned by the metamorphic rock model
- Landforms, geological formations and deposits as spatial entities
- Quarrying, mining, crushing and other production processes
- Finished stone products, masonry assemblies and concrete containing rock aggregate
- Soil and loose sediment as independently classified materials
Characteristics
- Petrographic identification
- Rock name, classification scheme, identification method and confidence; unidentified permitted Connects observations to a defensible material identity without treating an uncertain field name as established.
- Constituent composition
- Mineral and other constituent proportions in volume % or mass %, with method and detection limits Supports identification and helps explain strength, chemical reactivity and activity-specific hazards.
- Formation class
- Igneous, sedimentary, metamorphic or unresolved, with supporting evidence Routes the material to relevant narrower models and constrains interpretation of its texture.
- Grain size and fabric
- Grain-size distribution in mm; fabric descriptors; bedding or foliation orientation in degrees relative to a stated reference Reveals heterogeneity and directions along which the material may behave differently.
- Material occurrence and observation scale
- Links to specimen, fragment, outcrop or rock mass, with sampled extent and location Prevents measurements on a small intact specimen from being attributed uncritically to an entire rock mass.
- Density and pore structure
- Dry or saturated bulk density in kg/m³; total and connected porosity in %; method specified Supports estimates of mass, fluid uptake and susceptibility to environmental deterioration.
- Mechanical response
- Compressive and tensile strength in MPa; elastic modulus in GPa; loading direction, moisture and test method recorded Provides condition-specific evidence for handling, processing and load-bearing suitability.
- Discontinuity condition
- Fracture spacing, aperture and persistence in mm or m; orientation in degrees; infill and surface descriptions Identifies weaknesses that intact-rock strength alone does not describe.
- Weathering and alteration
- Observed changes and grade under a named assessment scheme, including depth and distribution Distinguishes current condition from the properties expected of fresh material.
- Use-specific constituent and release evidence
- Analyte-specific concentration, leachate or dust results with units, methods and reporting limits Supports decisions about a particular operation without assigning all rock one chemical identity or hazard classification.
Analytical facets
- substance
- material
- origin
- natural
- agency
- inert
- mobility
- varies
- scale
- not-applicable
- affordances
- observable
Also called
+56
Where this came from
oewn:2024 · CC BY 4.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 17 findings · 28 questions.
Rock identity and boundaries Establishes what geological material is being described and the scale at which statements apply.
Rock names, specimens and rock masses are easily conflated, producing misleading classifications and property assignments.
Material recognition
Separates rock material from mineral crystals, manufactured composites and unconsolidated material.
Aggregate and cohesion evidence
Record observations supporting treatment as rock, including constituent relationships and any uncertain consolidation boundary.
- What constituent relationships, texture and geological context support identification as rock rather than a mineral specimen or manufactured composite? definition
- Does weak cementation or disaggregation make the boundary with sediment or soil uncertain? boundary
Classification and scale
Connects the rock name to evidence and defines the material extent represented.
Supported name and represented extent
Record the naming scheme, identification confidence and relationship between the observed specimen and its parent occurrence.
- Which classification scheme and observations support the assigned rock name and broad formation class? provenance
- Do these observations describe a specimen, a material population or a fractured rock mass, and what evidence supports extrapolation? boundary
- If the material is metamorphic rock, which details should be delegated to that narrower model? boundary
Constituents and petrographic fabric Describes what the rock contains and how its constituents are arranged and joined.
Composition alone cannot explain rock behaviour without grain relationships, cementation and directional fabric.
Mineral and other constituents
Captures constituent identification, abundance and variation.
Composition with analytical basis
Record measured or estimated constituent proportions, explicitly separating mineralogy from bulk chemical composition.
- Which minerals, glass, organic matter or other constituents are identified, and by what method? measurement
- What are their proportions, uncertainty and variation across the sampled material? measurement
Grain relationships and fabric
Captures grain scale, bonding and preferred orientation.
Texture and directionality
Record grain-size distribution, interlocking or cemented relationships and visible bedding, foliation or other directional structures.
- What grain sizes, shapes and contact relationships are present, and what joins the grains? measurement
- Which fabrics define preferred directions, and how are those directions related to sampling and loading? measurement
Physical and mechanical behaviour Records measured rock behaviour with the conditions needed to interpret it.
Rock properties vary with pore structure, moisture, loading direction and test scale; a single unqualified material constant is inadequate.
Density, pores and water
Relates mass and void structure to water uptake and transport.
Pore system and moisture response
Record density, porosity and relevant fluid-response measurements without assuming that total porosity determines permeability.
- What are the dry and saturated bulk densities and the measured total and connected porosities? measurement
- What absorption or permeability measurements are available, and under which saturation, pressure and directional conditions? measurement
Strength and deformation
Captures intact-rock response to loading and the limits of available evidence.
Conditioned mechanical results
Associate strength and deformation results with specimen geometry, moisture, fabric direction and testing method.
- Which strength and stiffness results are available, with what units, specimen dimensions and test methods? measurement
- How do moisture, confinement and loading direction relative to fabric affect the results or limit their applicability? boundary
Fractures, weathering and durability Describes current damage and evidence of deterioration under relevant exposure.
Fresh intact rock can differ substantially from the fractured or weathered material an agent must actually assess.
Discontinuities and existing damage
Separates intact material properties from breaks and weakness surfaces.
Fracture geometry and condition
Record discontinuity geometry, surface condition and infill at the observation scale.
- What fracture sets, apertures, spacing, persistence and infill are observed? measurement
- Which observed weaknesses belong to the sampled rock and which require assessment of the surrounding rock mass? boundary
Alteration and exposure response
Connects present weathering to evidence about future deterioration.
Weathering profile and durability evidence
Record weathering indicators and relevant durability tests, distinguishing observed condition from predicted performance.
- What mineral alteration, discoloration, softening or disaggregation is observed, and how does it vary from surface to interior? measurement
- Which exposure-specific tests are needed to assess wetting and drying, freezing and thawing, salt crystallisation or chemical attack? action
Use suitability and material hazards Connects rock evidence to a specified operation or application.
Suitability and hazards depend on rock composition, condition and the intended activity rather than on the word rock alone.
Application and processing fit
Selects the material evidence required by the intended use.
Requirements linked to rock evidence
Compare the proposed use with tested properties, recoverable dimensions and fabric-related processing constraints.
- For the proposed use, which requirements govern strength, abrasion resistance, absorption, durability, appearance or chemical reactivity? action
- How do grain structure, bedding, foliation and fractures constrain cutting, splitting, crushing or recovery of usable blocks? action
Constituent and activity-dependent hazards
Determines what evidence is needed when an operation can release hazardous constituents.
Hazard evidence and applicable identity
Associate hazard and regulatory records with the actual material, identified constituents, activity and jurisdiction rather than inventing a universal rock identifier.
- Does the composition and intended activity warrant testing for respirable crystalline silica, asbestos minerals, leachable elements or other specific hazards? action
- Which verified classifications, substance identifiers or exposure criteria apply to this material or its constituents in the relevant jurisdiction? provenance
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.
- Rock is a broad material category with no single chemical formula, universal substance identifier, melting point, or hazard classification.
- Measurement ranges are indicative recall values, not design specifications; lithology, moisture, test method, and specimen condition must be established.
- Engineering assessments must distinguish intact rock specimens from rock masses, whose behaviour also depends on joints, faults, and groundwater.
- Which of these check these first hold for the sense of rock this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Igneous rock
- Sedimentary rock
- Metamorphic rock
- Which of these kinds and varieties hold for the sense of rock this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Crushed aggregate for concrete, asphalt, and road foundations
- Dimension stone for buildings, paving, and monuments
- Feedstock for cement and lime production where composition is suitable
- Source material for extracting metals and industrial minerals
- Riprap and armour stone for erosion control
- Which of these real-world use hold for the sense of rock this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Dry bulk density - Approximately 2200-3000 for many common compact rocks; porous and unusually mineral-rich rocks can fall outside this range - kg/m³
- Connected porosity - Below 1 in some dense crystalline rocks to above 30 in some porous sedimentary or volcanic rocks - %
- Uniaxial compressive strength of intact specimens - Approximately 5-250 for many rocks, with substantial variation outside this interval - MPa
- Which of these typical measurements hold for the sense of rock 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.
- Fracturing, joint movement, and weathering can destabilize rock masses and cause rockfalls or slope failures.
- Cutting, drilling, and crushing silica-bearing rock can generate hazardous respirable crystalline silica dust.
- Some rocks contain asbestos minerals or other hazardous constituents that can be released during disturbance.
- Freeze-thaw action, salt crystallization, and chemical alteration can cause cracking and disintegration.
- Some aggregates react adversely in concrete, including through alkali-silica reactions.
- Which of these failure modes and hazards hold for the sense of rock this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Available rock types and their engineering properties vary with local geological history and weathering conditions.
- Commercial stone names may differ from geological classifications and vary between markets.
- Which of these regional variation hold for the sense of rock 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.
- Mineral - A mineral is a naturally occurring crystalline substance with characteristic composition and structure; rock is a geological aggregate that can contain one or several minerals.
- Metamorphic rock - A subtype of rock whose composition, texture, or mineral assemblage has been altered predominantly in the solid state by changes in temperature, pressure, or fluid conditions.
- Sediment - Sediment consists of deposited particulate material that is generally unconsolidated; lithification can turn it into sedimentary rock.
- Ore - Ore is material from which a valuable constituent can be economically extracted under specified conditions; most rock is not ore.
- Stone - Stone commonly denotes a rock fragment or rock selected for practical use, rather than a separate geological material class.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of rock this model covers, and on what evidence? provenance
What the second pass must settle
- Does an existing Vercy world model already own this rock-material concept, requiring a link rather than a separate publication?
- How should the registry's mineral-aggregate definition handle predominantly glassy or organic rocks without silently widening its authoritative scope?
- Which classification conventions should govern weakly consolidated material at the boundary between rock, sediment and soil?
- Where should ownership of rock-mass discontinuities end in this material model and begin in a geological or geotechnical spatial model?
- Which application-specific test standards and jurisdiction-specific hazard sources must be researched before this draft can support operational decisions?