alabaster
Enable an agent to identify alabaster, assess a particular material specimen or lot, and decide whether its composition, condition and working properties suit a proposed use.
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 alabaster, assess a particular material specimen or lot, and decide whether its composition, condition and working properties suit a proposed use.
Alabaster is a fine-grained, commonly translucent ornamental stone, usually massive gypsum but also historically applied to banded calcite, valued for carving and decorative work.
It can be Resolve an alabaster label into a supported material identification or retain it as unresolved.; Select a block region and cutting orientation for a specified carving or thin-section requirement.; Compare lots for translucency, colour consistency, inclusions and usable yield.; Determine whether examination or compatibility testing is needed before cleaning, bonding or finishing.; Set evidence-based storage, display and handling conditions for the identified material.; Attach applicable working precautions to the actual composition, treatments and proposed operation..
Distinguishing features
Determine the dominant mineral phase before treating an alabaster label as an identification; archaeological usage can designate calcite where mineralogical usage designates gypsum. See [British Museum terminology](https://www.britishmuseum.org/collection/term/x10186).
Examine grain texture and aggregate structure rather than accepting white colour as sufficient evidence; gypsum alabaster is a fine-grained granular aggregate. See [UCL's description](https://www.ucl.ac.uk/museums-static/digitalegypt/stone/alabaster.html).
Check for casting features, binders and artificial filler using appropriate examination before distinguishing natural stone from manufactured imitation.
Compare mineral identification with texture when separating calcite-labelled alabaster from marble or other carbonate ornamental stones.
Measure transmitted light at a stated thickness and inspect coatings before using translucency to support an identification.
Scope
+ Mineralogical identification and the relationship between the recorded alabaster name and the actual material
+ Composition, accessory minerals, treatments and lot-specific grade
+ Grain structure, banding, translucency and usable stone dimensions
+ Cracks, surface alteration and environmental exposure history
+ Suitability for carving, polishing, thin sections and conservation treatment
+ Traceability and composition-dependent handling documentation
- Gypsum and calcite as general mineral species beyond their alabaster forms
- Cast plaster, resin and other manufactured alabaster imitations
- Finished sculptures, vessels and architectural elements except for their material condition
- Quarry operations and stoneworking machinery
- Artistic attribution, iconography and market valuation
Characteristics
- Alabaster naming sense
- gypsum alabaster | calcite-labelled alabaster | unresolved Prevents a shared name from transferring properties or treatment assumptions between different materials.
- Mineral composition
- Mineral phases and mass fractions in wt%, with method, uncertainty and detection limits Establishes the material basis for identification and use decisions.
- Source and lot association
- Links to specimen, block, supplier lot and documented quarry or locality Makes clear which material an analysis represents and how confidently its origin is known.
- Grain and band structure
- Grain size in µm or mm; band spacing in mm; orientation relative to the proposed cut Supports assessment of appearance, working direction and local variability.
- Optical transmission
- Transmittance in % at stated wavelength, thickness in mm and surface finish Allows comparison of stone intended for thin decorative sections or illumination.
- Surface treatment
- untreated | waxed | coated | dyed | impregnated | mixed | unknown, with substance where identified Treatments can affect appearance, analytical interpretation and compatibility with later work.
- Discontinuity condition
- Crack width and length in mm, location, orientation and evidence of change Constrains usable dimensions, support and permitted material removal.
- Water interaction
- Mass change in %, surface change and test duration under documented conditions Provides specimen-specific evidence for exposure and cleaning decisions.
- Thermal response
- Temperature in °C, duration, atmosphere, mass change in % and identified phase changes Avoids substituting an unsupported single melting point for observed material behaviour.
- Identity and handling documentation
- Applicable constituent identifiers, supplier safety documentation and jurisdiction-specific requirements Separates mineral or additive identities from the variable natural stone sold as alabaster.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.alabaster
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 34 questions.
Alabaster identity Separate the stone's name from its demonstrated mineralogical identity.
The alabaster label alone does not establish which material properties apply.
Name and sense
Preserve the original designation and its intended usage.
Recorded alabaster designation
Record whether the designation is mineralogical, archaeological, commercial or unresolved.
- Who called this material alabaster, and in what document or context? provenance
- Does that usage denote gypsum alabaster, calcite-labelled stone or only an appearance? definition
Mineralogical verification
Establish material identity independently of the label.
Phase and texture evidence
Combine mineral analysis and structural examination while recording identification confidence.
- What examination or analysis identifies the dominant mineral phase, and where was it performed? measurement
- What texture or binder evidence distinguishes this specimen from other gypsum forms, marble or cast imitation? boundary
- Can identification be strengthened without damaging a valued surface? action
Composition and origin Connect mineral composition and treatment history to a traceable specimen or lot.
A mineral name cannot stand in for the purity, additives or variability of a natural stone supply.
Stone constituents
Describe dominant and accessory phases separately from introduced substances.
Natural and added components
Establish what the tested stone contains and whether its surface represents the underlying material.
- Which accessory minerals or inclusions were detected, at what abundance and detection limit? measurement
- Are colour and surface sheen intrinsic, or associated with dye, wax, coating or impregnation? provenance
- What measured acceptance criteria define the claimed alabaster grade? definition
Quarry and lot evidence
Distinguish documented source information from geographic trade names.
Representative source link
Bind provenance and test results to the particular material they support.
- What evidence links this specimen or block to a quarry, locality or supplier lot? provenance
- How representative is the sampled region of the block's bands, inclusions and remaining volume? measurement
Texture and optical selection Assess alabaster's internal pattern and transmitted-light appearance at the intended working scale.
A visually suitable surface may conceal bands, opaque regions or defects that change the result after cutting.
Internal stone fabric
Map grain structure, bands, inclusions and discontinuities.
Usable region and orientation
Identify which part of the stone can deliver the required pattern and intact dimensions.
- Where do grain changes, bands, inclusions, voids and cracks intersect the proposed finished volume? measurement
- Which cutting orientation preserves the desired pattern while avoiding observed discontinuities? action
Transmitted-light appearance
Evaluate colour and translucency under reproducible viewing conditions.
Thickness-dependent appearance
Relate optical observations to thickness, lighting and finish.
- What colour and transmission are observed at the proposed thickness and illumination spectrum? measurement
- How much do banding, inclusions and surface treatment vary the appearance across the selected region? measurement
Condition and exposure Determine whether the identified alabaster is stable under its past and proposed conditions.
Cleaning, display and storage decisions require evidence about this stone's response and existing alteration.
Surface and moisture condition
Document changes associated with wetting, humidity, deposits and prior cleaning.
Surface change assessment
Distinguish deposited material from alteration or loss of the stone itself.
- Where are deposits, roughening, powdering, staining or loss of polish present, and what is their documented history? provenance
- What evidence distinguishes removable contamination from altered alabaster or an earlier finish? boundary
- What compatibility evidence is needed before any proposed wet cleaning? action
Thermal and fracture condition
Assess heat exposure and changing discontinuities without assuming a universal threshold.
Exposure-dependent stability
Associate physical or phase changes with measured exposure and monitoring evidence.
- What temperature, duration and humidity history is known, and has analysis identified any associated phase change? provenance
- Are mapped cracks or areas of surface loss changing between dated observations? measurement
- What tested operating conditions support the proposed display, including any nearby illumination source? action
Working and treatment decisions Translate identified composition and condition into justified fabrication and intervention choices.
The model must support decisions about a particular stone without treating a trade name as a complete working specification.
Carving and finishing
Evaluate achievable detail, section dimensions and finish through relevant material trials.
Operation suitability
Record evidence that the selected alabaster tolerates the intended operation and resulting geometry.
- What representative offcut trials establish cutting, carving and polishing behaviour for this lot? measurement
- What evidence supports the proposed minimum section, edge detail and support arrangement? action
- Would the proposed finish or adhesive visibly change colour or translucency? measurement
Composition-specific working controls
Associate working documentation with the actual mineral mixture, additives and operation.
Applicable identity and controls
Require verified applicability before attaching chemical identifiers, classifications or exposure requirements.
- Which CAS, EC or PubChem identifiers describe verified constituents, and which supplier records describe the stone mixture? boundary
- Which current classifications and exposure requirements apply to the identified composition and proposed dust-generating operation in the relevant jurisdiction? action
- What additional assessment is required for unknown coatings, impregnations or accessory minerals before working begins? 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 registry supplies no sense; establish whether the entry covers gypsum alabaster alone or includes historical calcite alabaster.
- Hardness and density are approximate constituent-based values; porosity, impurities and treatments affect individual stones.
- No sources were consulted; verify trade terminology, provenance and any applicable product standards before assigning regulatory identifiers.
- Which of these check these first hold for the sense of alabaster this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Gypsum alabaster
- Calcite alabaster
- Which of these kinds and varieties hold for the sense of alabaster this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Mineral composition - CaSO4·2H2O - Identifies the gypsum constituent of gypsum alabaster, not a standardized commercial stone grade.
- Mineral composition - CaCO3 - Identifies the calcite constituent of calcite alabaster; alabaster itself has no single chemical composition.
- Which of these identifiers and schemes hold for the sense of alabaster this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Carved sculpture and reliefs
- Decorative vessels and small ornamental objects
- Interior architectural ornament and facing
- Translucent lighting elements and panels
- Historic funerary and religious objects
- Which of these real-world use hold for the sense of alabaster this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Hardness of gypsum alabaster - Approximately 2 - Mohs scale
- Hardness of calcite alabaster - Approximately 3 - Mohs scale
- Density of gypsum alabaster - Approximately 2.3 - g/cm³
- Density of calcite alabaster - Approximately 2.7 - g/cm³
- Which of these typical measurements hold for the sense of alabaster 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.
- Soft surfaces scratch and abrade readily, particularly gypsum alabaster.
- Brittleness makes thin sections and projecting carved details vulnerable to fracture.
- Gypsum alabaster can dissolve and lose surface detail through prolonged water exposure.
- Acidic cleaners attack calcite alabaster.
- Cutting, grinding and sanding generate airborne mineral dust; impurities affect its hazards.
- Which of these failure modes and hazards hold for the sense of alabaster this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Modern European decorative-stone usage commonly means gypsum alabaster.
- In descriptions of ancient Egyptian objects, alabaster commonly means calcite stone, also described as Egyptian travertine.
- Commercial terms such as onyx marble may overlap with calcite alabaster and require mineralogical confirmation.
- Which of these regional variation hold for the sense of alabaster 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.
- Gypsum - Gypsum is the mineral; gypsum alabaster is its fine-grained massive ornamental variety.
- Selenite - Selenite denotes visibly crystalline, commonly transparent gypsum rather than fine-grained massive alabaster.
- Marble - Geological marble is a metamorphic carbonate rock; alabaster denotes ornamental gypsum or historically certain calcite deposits.
- Travertine - Travertine is carbonate rock deposited from water; some compact ornamental examples overlap with historical calcite alabaster.
- Onyx - Mineralogical onyx is banded chalcedony, whereas stone marketed as onyx marble is commonly carbonate.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of alabaster this model covers, and on what evidence? provenance
What the second pass must settle
- Does the registry intend alabaster strictly as gypsum alabaster, or also the historical and commercial calcite usage, and does an existing Vercy model already own either concept?
- Which authoritative test methods and acceptance criteria should define alabaster grades, translucency and usable defect limits for each intended use?
- What evidence supports moisture, temperature and cleaning limits for each identified variety, especially when prior treatments are unknown?
- Which constituent identifiers, mixture classifications and occupational requirements apply to actual supplied lots in the intended jurisdictions?
- How reliably can quarry origin and whole-block suitability be inferred from available documentation and limited sampling?