On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Trade name: geographic / origin-linked name · Natural identity; treatment status unknown
Ceylon Sapphire
Also known asSri Lankan sapphire
A trade name for sapphire historically associated with Sri Lankan sources; not a separate mineral species and no guarantee of origin. This page compares how the major standards and institutions name it, what must be disclosed when selling it, whether it can be worn every day, how it is treated and identified, and which source each conclusion comes from.
Price, rarity and origin are outside the scope of this wiki.
What this page can answer
This page covers
- How Ceylon Sapphire forms and what gives its colourFormation setting, process and timescale; where its colour and optical effects come from, each finding graded and sourced
- How to identify Ceylon SapphireIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Ceylon SapphireThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Ceylon SapphireCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of Ceylon SapphireEach value with its source and check date
- Ceylon Sapphire in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Which of GIA, FTC, CIBJO and Gem-A have a name for it on record, and do those agree?
- Listing and disclosing Ceylon SapphireThe listing name to use; what must be disclosed before sale
What we cannot conclude
- Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.
- Geographic origin, unless an origin report accompanies the item.
- Price, rarity or investment value: this wiki covers naming and disclosure only.
Material research: formation, causes and history
What authoritative sources say about how this material forms, what causes its colour and optical effects, where its name comes from and how people have used it. Each statement carries an evidence grade and its sources; it describes the material in general, not any specific piece.
How it forms
Ceylon sapphire refers to sapphire from Sri Lanka (historically Ceylon) and is a geographic trade name for sapphire (corundum). Sri Lanka's gem sapphires come from secondary placer deposits (e.g., Ratnapura, Balangoda) whose source rocks lie in the Highland Complex of Sri Lanka—part of a Precambrian granulite belt of the ancient Gondwana continent linked to Pan-African evolution. U-Pb dating of zircon inclusions in the sapphires gives ages of about 549 Ma, indicating crystallization coeval with end-Precambrian granulite-facies metamorphism.
Scope: Used to explain the nature of Ceylon sapphire as an origin trade name and its origin in Sri Lankan placer deposits / granulite-facies metamorphism; applies to samples of Sri Lankan origin.
Sources G&G Spring 2019
Where it forms
The Highland Complex of Sri Lanka, a Precambrian granulite-facies belt (Gondwana terrane linked to Pan-African evolution).
Sources G&G Spring 2019
Secondary placer (alluvial) deposits such as Ratnapura and Balangoda, where sapphire is concentrated after weathering and transport from its source rocks.
Sources G&G Spring 2019
How it forms, step by step
A late-Precambrian (~549 Ma) granulite-facies high-temperature event in Gondwana caused corundum to crystallize, enclosing zircon and other minerals.
Corundum was uplifted with the Highland Complex, weathered, eroded, and fluvially transported.
It concentrated into workable gem-quality sapphire in placers such as Ratnapura and Balangoda.
Its colour varies with trace elements: in low-iron material yellow comes from h•-Fe3+, and blue from Fe2+-Ti4+.
Link to appearance
Sri Lankan sapphires occur in blue and yellow: low-iron yellow from h•-Fe3+, blue from Fe2+-Ti4+; many display a 3161 cm⁻¹ OH feature indicating acceptor domination.
Sources G&G Spring 2020 · G&G Fall 2023
Timescale
Absolute ages are available: LA-ICP-MS U-Pb dating of zircon inclusions in two sapphires from the Ratnapura and Balangoda placers yielded about 549 Ma (557 Ma minus ~8.4 Ma uncertainty), coinciding with end-Precambrian granulite-facies metamorphism of Gondwana.
Sources G&G Spring 2019
Related base materials
- Corundum: Ceylon sapphire is sapphire from Sri Lanka (formerly called Ceylon); it is a geographic-origin trade name for corundum, not an independent material
Supporting findings
Sapphires from the Ratnapura and Balangoda placers in Sri Lanka were classified as metamorphic/metasomatic, non-basalt-related in origin based on trace elements and inclusions.
Evidence grade AScope: For the five Sri Lankan samples studied, not all Ceylon sapphire.
U-Pb dating of zircon inclusions in the sapphires gives about 549 Ma, indicating crystallization coeval with end-Precambrian granulite-facies metamorphism of Gondwana.
Evidence grade AScope: LA-ICP-MS U-Pb results for two samples, one from each placer.
Sri Lanka's Ratnapura and Balangoda gem placers lie within the Highland Complex. That complex is one segment of a broad Precambrian granulite belt belonging to the old Gondwana landmass, linked to Pan-African evolution, and taking in southern India's Kerala Khondalite Belt together with Madagascar, Mozambique, Tanzania and the Lütz-Holm Bay region of Antarctica.
Evidence grade AScope: Tectonic attribution is a literature-based synthesis.
Recorded localities
Authoritative sources name a single or principal locality.
Asia
- Ratnapura, Sri Lanka"Most notable localities" refers to Sri Lankan gem gravels generally.
Sources Gems & Gemology Summer 1982
- Balangoda, Sri Lanka
Sources Gems & Gemology Summer 1982
- Rakwana, Sri Lanka
Sources Gems & Gemology Summer 1982
- Elahera, Central Province, Sri Lanka
Sources Gems & Gemology Summer 1982
These are localities recorded by authoritative sources, not an origin finding for any individual piece. The CIBJO Gemstone Book (2022, §4.2.3) says a place of origin names where a gem was mined or harvested, is a matter of opinion, does not imply a level of quality, and that cutting, processing or exporting centres must not be used to imply origin. See how far testing can go on this page, the origin determination guide and the overview of recorded localities.
Causes of colour and optical effects
Sri Lankan sapphire colour can be set by different chromophores: low-iron yellow sapphires are coloured by h•-Fe3+, and blue by Fe2+-Ti4+.
Evidence grade AScope: Colour mechanism described with Sri Lankan examples.
How it is identified
The appearance of Ceylon (Sri Lankan) sapphire can closely match sapphires from other localities, and colour or appearance alone cannot prove its origin. Origin determination is a laboratory procedure based mainly on internal inclusion features and trace-element suites measured with instruments such as LA-ICP-MS and compared against reference data; origin conclusions carry overlap and uncertainty and must be issued by an accredited laboratory, and this entry gives no self-identification method or threshold.
Evidence grade AScope: Appearance is insufficient to settle origin; determination requires testing by an accredited laboratory, and this entry gives no self-test method or threshold.
In "Ceylon sapphire" the locality in the name is a trade attribution, not a determined origin. Origin labels for sapphire (corundum) (Sri Lanka, for instance) are often used to support a premium, yet origin cannot be inferred from appearance or name. Origin determination is a comparison against reference databases of known localities: a laboratory measures trace-element suites by LA-ICP-MS and weighs internal inclusion features against specimens of documented provenance. The judgement is relative - the characteristic ranges of different localities overlap, deposits with no reference material cannot be assigned, and a single deposit is internally variable; treatment alters the measurable features, so treatment status must be settled first. An origin call must be issued by an accredited laboratory for a specific specimen, and "consistent with a locality" is not the same as "mined there"; nor does a place name in the trade prove quality.
Evidence grade AScope: Origin cannot be inferred from appearance or name; the locality in the name is a trade attribution, not a determined origin; a conclusion must be issued by an accredited laboratory for a specific specimen; no self-test criteria are given here.
Other research findings
‘Ceylon (Sri Lanka)’ is a place name used only to denote where a gem was mined or harvested; under CIBJO, origin determination is a matter of opinion, and origin does not imply quality.
Evidence grade AScope: CIBJO naming/place-of-origin rules.
Sources CIBJO Gemstone Book 2022
Most gem-quality sapphires come from secondary placer deposits whose crystallization setting cannot be observed directly, so origin determination relies on indirect evidence such as geochemistry and inclusions.
Evidence grade AScope: General statement on placer occurrence and origin-determination methods.
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The ~549 Ma age rests on zircon inclusions in just two placer samples.
- Sri Lankan sapphire is mostly recovered from placers, so source-rock conditions are inferred; samples cover only Ratnapura and Balangoda.
- The place-name rules for ‘Ceylon’ follow CIBJO (level A); origin determination is an opinion.
Methodology
- Origin determination and its limits
- Quality grading and value factors
- How gemmology became a technical discipline
Evidence grades
- A
- Standards bodies, government geological surveys, peer-reviewed research and museum records
- B
- Institutional educational material
- C
- Specialist databases or cautious readings
A statement is never graded above its strongest source.
This section is LumaLark's own factual restatement of public authoritative sources, credited item by item; it contains no verbatim excerpts, images or third-party logos.
DecideListing name, disclosure, care and treatments
- Suggested listing name
- Sapphire (any geographic-origin opinion requires a laboratory report)
16 CFR Part 23 §23.1
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated (via parent material), Dyed (via parent material), Filled / Fracture-filled (via parent material), Diffusion-treated (via parent material), Irradiated (via parent material)
Related:Disclosure and cautions
This page cannot answer
Natural? · Origin · Price
A lab report settles these; this wiki covers naming and disclosure.
Related:What this page can answer
Answer at a glance
"Ceylon Sapphire" is a market name rather than a mineral species name; before using it, verify: Laboratory identification required before the name is used.
Evidence
What this means for you
Before buying, check the recommended listing name "Sapphire (any geographic-origin opinion requires a laboratory report)" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
Known uncertainty
- This entry's exact material identity is not fully settled.
- See “Disclosure and cautions” above
- Last reviewed
- 2026-09-01
Trade-name ruling
- Laboratory identification required before the name is used.
- Suggested listing name
- Sapphire (any geographic-origin opinion requires a laboratory report)
Care and wear
The item-by-item care advice that the GIA Care and Cleaning Guide gives for the whole class, and so for Ceylon Sapphire, is set out in full under care on the Sapphire entry.
Care
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Treatments and identification leads
One row per treatment, with three standards side by side: how often it occurs and how stable it is (CIBJO), its category in GB/T 16552—2017 Table B.1 (this site's paraphrase) and how the JJA/AGL 2025 table lists it. Each CIBJO value links to its entry under “Testing and market”, where the wording and source are given in full.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| Heating | — | — | Optimization | — | — |
| Dyeing | — | — | Treatment | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Diffusion | — | — | Treatment | — | — |
| Irradiation | — | — | Treatment | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Sapphire)
Whether a treatment has to show in the name differs between the two rule sets (this site’s paraphrase):
- GB/T 16552—2017: a method classed as treatment has to be stated in the name itself — the method put before the name, or added in brackets after it; a method classed as optimization does not need to appear in the name, though one marked “Optimization (annotation required)” still has to be noted in the quality documents. Source: §5.4.2.1 a), b); §5.4.2.2 a)
- CIBJO Gemstone Book 2022: no longer splits treatments into ones that need specific disclosure and ones that need only general disclosure: every treatment is to be disclosed, and the seller tells the buyer which treatment was used and what special care it calls for. Source: §4.2.5 Note 2, §4.2.5.1, pp.14–15
What this table covers
What this page can give
- Registered treatments, their stability and how often they occur (see the table above)
- Identification leads for each treatment, for use when sending a stone for testing
How lab reports word it
Report wording for Ceylon Sapphire is set out under report wording on the Corundum entry.
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Ceylon Sapphire, the name register records "Sri Lankan sapphire", for which no restriction on use as a name is recorded.
Names in four languagesNames for Ceylon Sapphire are registered in Simplified Chinese, Traditional Chinese, English (Ceylon Sapphire) and Japanese. Chinese standard nameThe GB/T 16552—2017 naming counterpart is sapphire, and Ceylon Sapphire itself is not listed in the standard. Trade and mineralogical namesAnother common market name is the English Sri Lankan sapphire. The mineralogical name describes sapphire historically associated with Sri Lanka and recognised as a trade variety. Recommended listing nameThe suggested listing name is Sapphire (an origin opinion requires a laboratory report). Institution usageOn authority wording, GIA records Ceylon Sapphire, with a qualifying note that it is a geographic variety; the FTC records Sapphire, with the qualification that “Ceylon” implies Sri Lankan origin and that unverified origin claims are deceptive; the CIBJO text on file has no wording for this name (checked); Gem-A is unchecked. Where Ceylon Sapphire appears under bodies that have no recorded wording or are unchecked, it is the entry's own English name and does not represent their position. Japanese namesThe GSJ (Japan) formal name corresponds to Ceylon sapphire, but the wording used by the GSJ for this name is not yet verified by this site, and the entry's own Japanese name is shown.
Name register
Every name recorded for this entry, with how it is classified, whether it may be matched to this entry automatically, whether it may be used as a product name, and the clause it rests on.
This table scrolls sideways on narrow screens.
| Name | Type | Matching | Use as a name | Basis |
|---|---|---|---|---|
| no restriction recorded (1) | ||||
| Sri Lankan sapphireEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- セイロン・サファイア (not yet checked for this body — the entry's own Japanese name is shown)
- GB/T naming counterpart (this name is not in the standard)
- 蓝宝石 (GB/T 16552—2017 §5.1.2.1 b))
- Mineralogical name
- Sapphire historically associated with Sri Lanka; recognised as a trade variety
- Trade names and synonyms
- Sri Lankan sapphire (market name)
Four-language names
- 简体中文
- 锡兰蓝宝石
- 繁體中文
- 錫蘭藍寶石
- English
- Ceylon Sapphire
- 日本語
- セイロン・サファイア
Qualifiers stripped from the headline name
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Oxide minerals
- Identity tier
- Trade name: geographic / origin-linked name
- Mineral chemical class
- Oxides / hydroxides
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
For the treatments listed by standards, this site applies the “Sapphire” row of GB/T 16552—2017, Annex B, Table B.1 to Ceylon Sapphire: heating is listed as an optimization, dyeing as a treatment, filling as graded, diffusion as a treatment and irradiation as a treatment. The full Table B.1 row, with the effect column, is on the Sapphire page; what Table B.1 is and how filling is graded are on the Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Under the “Sapphire” row of Table B.1: Heating Optimization; Dyeing Treatment; Filling Graded — see §5.4.1, Table 1; Diffusion Treatment; Irradiation Treatment. The full row, with the effect column, is on the Sapphire page.
What Table B.1 is, and how the “see 5.4.1” grades are defined: see the GB/T 16552: optimization vs treatment page.
What it is and how it's identified
In the registered material facts for Ceylon Sapphire, rows that name a class give values for sapphire as a whole (regardless of colour and origin), not measurements of Ceylon Sapphire itself: crystalline, trigonal, with a hexagonal prismatic or barrel-shaped habit, occasionally tabular or bladed; Mohs hardness 9, no cleavage, though well-twinned stones may show parting in three directions; optic character anisotropic, uniaxial, optically negative, birefringence 0.008–0.01; asterism visible, commonly as six-rayed stars; for refractive index the cited clause gives 1.762–1.770 with a stated tolerance of (+0.009, −0.005), registered as 1.757–1.779, the range worked out from that; for density the cited clause gives 4.00 with a stated tolerance of (+0.10, −0.05), registered as 3.95–4.1 g/cm³, the range likewise worked out from that. Untreated, pleochroism is strong and varies with body colour, and the lustre is vitreous to subadamantine.
Registered material facts
Each row carries its own source and check date and can be cited on its own; “—” means the cited source gives no value, not “none”.
Chemical composition, luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for sapphire as a whole (all colours and origins), so they are not repeated on the Ceylon Sapphire page; see the material facts on the Sapphire entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Ceylon Sapphire (how to read class-level values).
Structure
Ceylon Sapphire — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — structure (crystal system): trigonal
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — structure (crystal habit): hexagonal prisms or barrel shapes, occasionally tabular or bladed.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Ceylon Sapphire — Mohs hardness: 9
GB/T 16553—2017
Reference points on this site: Talc 1–3, Fluorite 4, Apatite 5–5.5, Orthoclase 6–6.5, Topaz 8, Diamond 10 (Source: GB/T 16553—2017); Gypsum 1.5–2, Calcite 3, Quartz 7 (Source: Handbook of Mineralogy); Corundum 9 (Source: GIA Gem Encyclopedia (care guide))
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — cleavage: no cleavage; stones with well-developed twinning may show parting in three directions.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Ceylon Sapphire — density: 3.95–4.1 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
- Qualification
The clause we cite gives 4.00, with a stated tolerance of +0.10 / -0.05. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Ceylon Sapphire — optic character: uniaxial, optically negative (anisotropic)
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — refractive index: 1.757–1.779
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
- Qualification
The clause we cite gives 1.762–1.770, with a stated tolerance of +0.009 / -0.005. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — birefringence: 0.008–0.01
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — pleochroism: strong; blue, greenish blue
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
"Strong" comes from the field's general statement (strong, varying with colour); what follows is the value the clause gives for this colour.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 Pleochroism · Blue (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — pleochroism: strong, and varying with color: blue shows blue and green-blue; green shows green and yellow-green; yellow shows yellow and orange-yellow; orange shows orange and orange-red; pink shows pink and pink-red; purple shows purple and purple-red.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — fluorescence (overall): long wave none to strong, orange-red; short wave none to weak, orange-red.
GB/T 16553—2017
UV fluorescenceorange-rednone–strongorange-rednone–weakDots are illustrative colours built from the colour names, not measured values
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 Fluorescence (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — spectrum (UV-visible): blue, green, yellow: 450 nm absorption band; or 450 nm absorption peak; 460 nm absorption peak; 470 nm absorption peak.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 UV-visible spectrum (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — optical effect (asterism): seen; commonly a six-rayed star
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Ceylon Sapphire — optical effect (colour change): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- asterism, colour change
Quality factors
Ceylon Sapphire — quality factor (lustre): vitreous to subadamantine
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- sapphire as a whole (all colours and origins)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.3 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
This material (RI / SG midpoints): 1.768 / 4.03; Closest values: 1Rhodolite 1.755 / 3.9, 2Almandine 1.79 / 3.9, 3Grossular 1.745 / 3.9, 4Tsavorite 1.74 / 3.9, 5Spessartine 1.802 / 3.9
Show the full chart (330 registered materials)
Outside the full chart's range, drawn as triangles at the edge (RI / SG midpoints): Hematite 3.045/5.12, Synthetic Rutile 2.76/4.26, Rutile 2.753/4.23, Synthetic Moissanite 2.67/3.22
Testing and market
The CIBJO laboratory protocol covers Ceylon Sapphire under “Sapphire” (§6.1.69): see identification on the Sapphire entry; the required tests are listed on the CIBJO laboratory protocol table for Sapphire.
How far testing can go
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Evidence and sources
Authority basis and clause sources
Sources
- CIBJO – The World Jewellery Confederation. Gemmological Laboratories Book (Blue Book), Gemmological Commission 2024-1.
- CIBJO – The World Jewellery Confederation. The Gemstone Book (Blue Book), 2022.
- SAMR / SAC (China). GB/T 16552—2017 Gems — Nomenclature.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia.
- Gem-A – The Gemmological Association of Great Britain (United Kingdom).
- eCFR (United States). 16 CFR § 23.1 — Deception (general). In: 16 CFR Part 23 — Guides for the Jewelry, Precious Metals, and Pewter Industries.
Further reading
Related entries and topic cluster
Parent entry and related pages on this site. Rows marked “Planned” are suggested new content and have no link yet.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Oxide minerals | Live |
| Treatments recorded for this material | Heated / Heat-treated (via parent material), Dyed (via parent material), Filled / Fracture-filled (via parent material), Diffusion-treated (via parent material), Irradiated (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Ceylon Sapphire entry are maintained by the LumaLark wiki and matched one by one to the standard clauses or institutional sources they cite: every fact carries its source (with a clause or page locator) and a check date, so it can be traced back to the original. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.