On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral / gemstone variety · Natural; common industry optimization (verify with certificate)
Yellow Sapphire
A yellow gem variety of corundum; some colours may fade, and irradiation, diffusion and heat treatment must all be disclosed. 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 Yellow 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 Yellow SapphireIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Yellow SapphireThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Yellow SapphireCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of Yellow SapphireEach value with its source and check date
- Yellow 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 Yellow SapphireThe listing name to use; what must be disclosed before sale
- Standard clauses that define Yellow SapphireWhich clause defines it, each cross-checked
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
Yellow sapphire is not a species of its own but a colour variety of corundum. In nature its yellow comes from either of two quite distinct chromophores, or from both at once. The first is Fe3+, which absorbs blue light around 450 nm and so transmits yellow, but it is a weak colouring agent and must be present at several thousand ppma to matter. The second—a trapped hole paired with Fe3+ (h•-Fe³⁺)—is roughly a thousand times stronger and needs only a few ppma; on its own it gives colour to the low-iron yellow sapphires of Sri Lanka. Because h•-Fe³⁺ develops in stones where acceptors dominate, colourless or faintly yellow material may be heat-treated to generate it and thereby turn yellow.
Scope: Applies to the colour explanation of the natural yellow corundum gem variety (Fe3+ and h•-Fe³⁺); synthetic yellow sapphire is commonly coloured by Ni3+ or Ni³⁺+Cr3+ and falls outside this scope.
Sources G&G Fall 2023 · G&G Spring 2020
Where it forms
The same natural corundum-forming settings as other sapphires, with yellow sapphires found across many localities; low-iron, acceptor-dominated stones (e.g. Sri Lanka) are coloured by h•-Fe³⁺ alone, while high-iron basalt-hosted stones (e.g. Australia, Thailand) often carry both Fe3+ and h•-Fe³⁺.
Sources G&G Fall 2023
How it forms, step by step
Fe3+ substitutes for Al3+ as corundum crystallises; its absorption near 450 nm removes blue light and the transmitted colour is yellow.
When the stone is acceptor-dominated (excess divalent cations such as Mg2+ and relatively high oxygen fugacity), a trapped hole h• forms for charge compensation and pairs with Fe3+ as the h•-Fe³⁺ chromophore.
Where Fe3+ and h•-Fe³⁺ coexist their absorptions add; if a stone is colourless or weakly yellow and hydrogen-poor, heat treatment in oxygen can generate h•-Fe³⁺ and deepen the yellow.
Link to appearance
The 450 nm Fe3+ band is the main cause of yellow but requires high concentrations because the chromophore is weak; the h•-Fe³⁺ chromophore has a large cross section and a few ppma give similar or stronger yellow, and the two together can give intense colours up to “Mekong Whisky”.
Sources G&G Fall 2023
Timescale
The cited sources give no absolute timescale for yellow sapphire formation.
Sources G&G Fall 2023
Related base materials
- Corundum (Al2O3): color variety of corundum
Supporting findings
The h•-Fe³⁺ chromophore forms in acceptor-dominated natural stones, so colourless or weakly yellow, hydrogen-poor stones can be heat-treated in oxygen to create it and become yellow.
Evidence grade AScope: Describes the chromophore's formation conditions; the heat-treatment route is a laboratory-controlled process.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Sri LankaLow-iron type, colored solely by the h•-Fe3+ chromophore
- ThailandBasalt-hosted high-iron sapphire
Oceania
- AustraliaBasalt-hosted high-iron sapphire
Sources G&G Fall 2023 · Gems & Gemology Fall 1985
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
In natural yellow sapphire the colour arises either from one of two quite distinct chromophores or from both together: iron in the Fe3+ state, and a trapped hole associated with iron (h•-Fe³⁺).
Evidence grade AScope: Concerns natural yellow sapphires; synthetic yellow sapphire is often coloured by Ni3+.
Fe3+ is the weakest chromophore in natural corundum, needing several thousand ppma for strong yellow; its 450 nm band absorbs blue light so that the transmitted colour is yellow.
Evidence grade AScope: Based on quantitative observations for faceted stones up to several carats.
The h•-Fe³⁺ chromophore is about 1000 times as strong, giving strong yellow from only a few ppma, and is the primary cause of colour for Sri Lanka's low-iron yellow sapphires.
Evidence grade AScope: The strength ratio is an order-of-magnitude comparison (about 1000×), not an exact constant.
How it is identified
Yellow sapphire can be confused with other yellow gems; colour alone does not settle identity or source. Laboratories combine several lines of evidence: magnification of inclusions and growth features; routine tests such as refractive index, specific gravity and polariscope behaviour; ultraviolet fluorescence; and spectroscopy (for example FTIR, UV-Vis-NIR and Raman). Trace-element chemistry measured by EDXRF or LA-ICP-MS helps separate natural from synthetic corundum and, compared with a reference collection, may point to a geographic origin; glass-filled fractures and coatings are caught by clues such as anomalous luster, gas bubbles, X-ray radiography, and FTIR or EDXRF signatures. Origin calls can remain inconclusive, so the finding should be issued by a qualified gem laboratory.
Evidence grade AScope: Applies where natural, synthetic and treated corundum, and geographic origin, must be assessed; no self-administered criteria are given.
Sources G&G Summer 1998 · G&G Winter 2019 · G&G Fall 2019 +2
- Separating Natural and Synthetic Rubies on the Basis of Trace-Element Chemistry (Gems & Gemology, Summer 1998, Vol. 34, No. 2)
- Geographic Origin Determination of Ruby (Gems & Gemology, Winter 2019, Vol. 55, No. 4)
- Cobalt-Coated Sapphire (Lab Notes, Gems & Gemology, Fall 2019, Vol. 55, No. 3)
- Translucent Ruby Filled with Zinc Glass (Lab Notes, Gems & Gemology, Fall 2023, Vol. 59, No. 3)
- Bismuth Glass-Filled Burmese Star Ruby (Lab Notes, Gems & Gemology, Spring 2020, Vol. 56, No. 1)
Yellow sapphire may be priced on locality, with goods traded under names such as Sri Lanka, Madagascar or Montana. A locality name, however, is only a trade attribution and is not a determined origin. Origin work is a laboratory exercise: the deposit type is addressed first, then inclusion suites and trace-element suites (measured by methods such as laser ablation ICP-MS) are compared with reference databases for known localities to yield a conclusion of consistency or inconsistency with a source. Because the characteristic ranges of different localities overlap and vary within a single deposit, the conclusion is probabilistic and may be only inconclusive; heating, filling and diffusion alter the measurable features and must be excluded first. Origin cannot be inferred from appearance or name; an origin conclusion must be issued by a qualified laboratory for a specific specimen. This entry offers no self-test criteria or thresholds.
Evidence grade AScope: Origin cannot be inferred from appearance or name; an origin conclusion must be issued by a qualified laboratory for a specific specimen, and this entry provides no self-test criteria or thresholds.
Sources G&G Winter 2019 · G&G Summer 1998 · G&G Spring 2015 +1
- Geographic Origin Determination of Ruby (Gems & Gemology, Winter 2019, Vol. 55, No. 4)
- Separating Natural and Synthetic Rubies on the Basis of Trace-Element Chemistry (Gems & Gemology, Summer 1998, Vol. 34, No. 2)
- Mozambique Ruby Discovery: A 21st Century Rush (Gems & Gemology, Spring 2015, Vol. 51, No. 1)
- Sapphire Beneath the Rich Black Soil of Muling, Northeastern China (Gems & Gemology, Fall 2022, Vol. 58, No. 3)
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The cited sources give no absolute timescale for yellow sapphire formation.
- The Fe3+ chromophore strength depends non-linearly on concentration, and the source notes that its physical model remains incomplete.
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
- Yellow Sapphire
IMA Mineral List 2026-07 “Corundum” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.265 “Yellow sapphire”
Construction or treatment status
Natural; common industry optimization (verify with certificate)
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
Yellow Sapphire is Yellow corundum gem variety; use "Yellow Sapphire" for listings, and disclose any known treatments.
Evidence
- CIBJO · 7.2.1.265
What this means for you
Before buying, check the recommended listing name "Yellow Sapphire" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
Known uncertainty
- Last reviewed
- 2026-09-01
Care and wear
Normal care for every gemstone (CIBJO Gemstone Book §6.1), in brief:
- Handle it gently.
- Store pieces apart when not worn, so they cannot scratch each other.
- Clean with warm soapy water and a soft brush.
- Use ultrasonic cleaners only with caution.
The §6.1 wording and the full list of §6.2 special-care letters cited on this page are on the general gem care page.
The item-by-item care advice that the GIA Care and Cleaning Guide gives for the whole class, and so for Yellow Sapphire, is set out in full under care on the Sapphire entry.
Care
Yellow Sapphire — care (re-cutting): Stones with superficial colour and surface layers are not suitable for re-cutting or re-polishing.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code m
- Treatment state
- treated
- Only after these treatments
- irradiation
Source & check 2026-09-25
- Source
- Fact checked on
- 2026-09-25
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Durability and wearing
Toughness
Excellent
Sources GIA Gem Encyclopedia (care guide)
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 Yellow Sapphire is set out under report wording on the Corundum entry.
A general LMHC wording rule also covers Yellow Sapphire (Information Sheet #16): see the LMHC rule “Colour stability testing”.
VerifyNames, standards, technical facts, clauses and sources
Names
Standard and listing namesThe GB/T 16552—2017 formal name corresponding to Yellow Sapphire is sapphire (Table A.1), and this name itself is not listed in the original; the suggested listing name is Yellow Sapphire. Names in four languagesFour-language names are given in Simplified Chinese, Traditional Chinese, English (Yellow Sapphire) and Japanese. Institution usageOn authority wording, CIBJO records Yellow Sapphire (CIBJO Gemmological Laboratories Book 2024), the FTC text on file has no wording for this name (checked), and GIA and Gem-A are unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. Japanese namesThe entry has its own Japanese name, and the wording of Japan's GSJ for this name is not yet verified by this site.
- GSJ (Japan) formal name
- イエローサファイア (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 Table A.1)
- Mineralogical name
- Yellow corundum gem variety
Four-language names
- 简体中文
- 黄色蓝宝石
- 繁體中文
- 黃色藍寶石
- English
- Yellow Sapphire
- 日本語
- イエローサファイア
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
- Mineral / gemstone variety
- Mineral chemical class
- Oxides / hydroxides
- Construction or treatment status
- Natural; common industry optimization (verify with certificate)
Treatments listed by standards
For Yellow Sapphire, this site applies the "Sapphire" row of GB/T 16552—2017 Annex B, Table B.1, listing: heating, category optimization; dyeing, category treatment; filling, category determined by grade; diffusion, category treatment; irradiation, category treatment. The full content with the effect column is on the Sapphire page; what Table B.1 is, and how the filling grades are defined, are on this site's 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
The composition of Yellow Sapphire is corundum. Structure, hardness, cleavage, density, optic character, refractive index and birefringence are registered for sapphire as a whole (all colours and origins), not measured separately: crystalline, trigonal; Mohs hardness 9; no cleavage, though twinned stones may show three directions of parting; density 3.95–4.1 g/cm³ (clause value 4.00, tolerances +0.10 and −0.05, from which the range is derived); anisotropic, uniaxial, negative; refractive index 1.757–1.779 (clause value 1.762–1.770, tolerances +0.009 and −0.005, from which the range is derived); birefringence 0.008–0.01; lustre, untreated, registered for sapphire as a whole as 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 Yellow 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 Yellow Sapphire (how to read class-level values).
Definition
Yellow Sapphire — composition (phase): corundum
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow 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
Yellow Sapphire — pleochroism: strong; yellow, orangey yellow
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 · Yellow (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Yellow Sapphire — fluorescence (overall): long wave none to moderate, orange-red, orange-yellow; short wave weak, red to orange-yellow.
GB/T 16553—2017
UV fluorescenceorange-redorange-yellownone–moderateredorange-yellowweakDots 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
Yellow 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
Yellow 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
Yellow 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
Yellow Sapphire — body colour: Greenish yellow to orangish yellow.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Andalusite, Canary Tourmaline, Chrysoprase and other entries also name yellow or a yellowish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
- CIBJO definitions
- asterism, colour change
Quality factors
Yellow 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 Yellow 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.
Clause-level definitions
Yellow Sapphire has a direct definition in the CIBJO Gemmological Laboratories Book 2024 under the term Yellow sapphire, defined as a greenish-yellow to orangey-yellow variety of corundum. The cross-check result is recorded as defined directly by CIBJO, with no identically named English entry found in this edition of the GB/T annex.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Yellow sapphire | 7.2.1.265 | Greenish yellow to orangish yellow variety of corundum | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
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.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- Geological Survey of Japan, AIST (Japan). Museum mineral specimens, browse by classification.
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.
Related-entry tree for Corundum on this site: 18 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Yellow Sapphire) is marked.
- Corundum
Sub-entries (13)
- Colour-change Sapphire
- Green Sapphire
- Orange Sapphire
- Padparadscha Sapphire
- Pink Sapphire
- Purple Sapphire
- Ruby
Sub-entries (2)
- Lead-Glass-Filled Ruby
- Synthetic Ruby (Synthetic product)
- Sapphire
Sub-entries (2)
- Beryllium-Diffused Sapphire
- Synthetic Sapphire (Synthetic product)
- Star Ruby
- Star Sapphire
- Synthetic Corundum (Synthetic product)
- White Sapphire
- Yellow Sapphire
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 Yellow 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; clause-level definitions also carry a cross-check result. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.