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UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral / gemstone variety · Natural identity; treatment status unknown
Orange Sapphire
A yellow-orange to red-orange variety of gem corundum. It differs from Padparadscha Sapphire (a controlled color range between pink and orange), and CIBJO Appendix C also lists Pink-Orange sapphire on its own line. 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 Orange 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 Orange SapphireIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Orange Sapphire3 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing Orange SapphireCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of Orange SapphireEach value with its source and check date
- Orange 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 Orange 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
Orange sapphire is one of the colour varieties of corundum (Al2O3) — gem corundum ranging from yellowish orange to reddish orange — and its material remains corundum/sapphire rather than something distinct. The orange hue derives chiefly from the trapped-hole/chromium (h•-Cr3+) chromophore: within corundum a trapped hole (O−) coupled with Cr3+ gives a strong orange, and when more Cr3+ is present the result is a pinkish orange (padparadscha). Such stones come from ordinary corundum deposits (metamorphic or placer settings), and heat treatment can create or enhance the colour as well (for instance the 14.62 ct heated Sri Lankan stone noted elsewhere in this record).
Scope: Used to explain that orange sapphire is a colour variety of corundum (not an independent material), the h•-Cr3+ mechanism of its orange colour, and that heat treatment can produce orange colour.
Sources CIBJO Gemstone Book 2022 · G&G Spring 2020 · G&G Fall 2023
Where it forms
General corundum-deposit settings: metamorphic/non-basalt-related crystallization settings and secondary placers (orange is a chromophore state, not locality-bound).
Sources G&G Spring 2020 · G&G Fall 2023
Low-iron settings (e.g., Sri Lanka): with chromium, h•-Cr3+ orange can form; with iron, h•-Fe3+ yellow dominates.
Sources G&G Spring 2020 · G&G Fall 2023
How it forms, step by step
As corundum crystallizes, acceptors such as Mg and charge compensators such as hydrogen can generate or suppress trapped holes (h•).
In warm, dry conditions hydrogen diffuses out, leaving trapped holes; the hole preferentially pairs with Cr3+ to form h•-Cr3+.
h•-Cr3+ absorbs visible light strongly, giving orange (yellowish orange); with coexisting Cr3+ the colour shifts to pinkish orange (padparadscha).
Orange can also be produced or enhanced by heat treatment (e.g., a heated Sri Lankan orange sapphire); only 20-40 ppma Cr3+ suffices for a noticeable colour shift.
Link to appearance
Orange results from the h•-Cr3+ chromophore (a strong orange); combined with Cr3+ it turns pinkish orange (padparadscha). One example: the heated Sri Lankan sapphire of 14.62 ct noted above.
Sources CIBJO Gemstone Book 2022 · G&G Spring 2020
Timescale
Orange sapphire has no dedicated absolute age: orange is a chromophore (h•-Cr3+) state, not a datable geological event, and these sources give no age for orange samples. The host corundum's crystallization age can be dated elsewhere via U-Pb on zircon inclusions (e.g., ~549 Ma in Sri Lanka), but that is the host rock's age, not the age of ‘orange’.
Sources CIBJO Gemstone Book 2022 · G&G Spring 2020 · G&G Fall 2023
Related base materials
- Corundum: Orange sapphire is a gem variety of corundum (sapphire) defined by colour; the material is corundum, not an independent material
Supporting findings
Orange sapphire occurs in general corundum settings: in low-iron material yellow sapphire is coloured by h•-Fe3+ (e.g., Sri Lanka); with chromium the h•-Cr3+ chromophore produces orange, so orange and other colours arise in the same kinds of deposits.
Evidence grade BScope: Deposit relationship inferred from chromophore examples; no quantitative orange-production data per deposit.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- East Africa1990s East African discoveries increased fancy-color supply
Sources GIA Gem Encyclopedia
- Madagascar
Sources GIA Gem Encyclopedia
Asia
- Sri LankaLab-note sample of Sri Lankan origin; traditional fancy sapphire source
Sources Gems & Gemology Winter 2021 · GIA Gem Encyclopedia
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
Orange in corundum is produced mainly by the trapped-hole/chromium (h•-Cr3+) chromophore: where a trapped hole pairs with Cr3+, natural corundum shows a strong orange colour.
Evidence grade AScope: Colour mechanism, with spectra measured partly on synthetic material.
The pinkish orange of padparadscha sapphire is produced by the h•-Cr3+ and Cr3+ chromophores acting together.
Evidence grade AScope: Colour mechanism; not the definition of padparadscha's colour range.
The h•-Cr3+ chromophore has a large absorption cross section; only 20-40 ppma Cr3+ is sufficient to shift the colour of corundum noticeably toward orange.
Evidence grade AScope: Based on measured cross sections and synthetic quantitative results.
How it is identified
Rubies and sapphires that look alike may be natural, synthetic or treated, and the unaided eye with routine methods cannot decide reliably — synthetic material may even lack diagnostic inclusions and growth features. Laboratory separation rests on measurable properties: trace-element chemistry such as energy-dispersive X-ray fluorescence (EDXRF) can flag synthetic stones by the presence of trace elements including Ni, Mo, La, W, Pt, Pb and Bi, while Ga/Mg/Fe/Ti fingerprints and inclusion scenes support origin calls; glass filling and coating (for example cobalt coating marked by facet-junction and surface speckling) must be detected under magnification and instrumentation. Limitations: origin determination relies on reference databases and involves overlap between sources, so it carries uncertainty; the final conclusion must be issued by an accredited gemological laboratory through testing.
Evidence grade AScope: Identification and separation points; origin determination is uncertain and must be issued by an accredited gemological laboratory, and no self-test thresholds are given.
Origin labels for orange sapphire (Sri Lanka, China, and elsewhere, 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 inclusion features such as rutile silk, clouds, and growth zoning 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; heating and other treatments alter the measurable features, so treatment status must be settled first, and an individual stone may therefore return an "inconclusive" result. 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".
Evidence grade AScope: Origin cannot be inferred from appearance or name; conclusions are probabilistic and must be issued by an accredited laboratory for a specific specimen; no self-test criteria are given here.
Other research findings
Heat treatment can also create or strengthen orange in sapphire; a heated Sri Lankan sapphire of 14.62 ct, coloured orange, illustrates what the h•-Cr3+ chromophore produces in isolation.
Evidence grade AScope: Uses a heated sample to illustrate the chromophore; process parameters not covered.
'Orange sapphire' is a colour-variety name for corundum. CIBJO allows a colour description placed before or after the proper mineral name to stand in for any variety or trade name — so orange sapphire remains corundum.
Evidence grade AScope: CIBJO naming rule (clause 4.2.4).
Sources CIBJO Gemstone Book 2022
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- Orange sapphire has no dedicated absolute age; orange is a chromophore (h•-Cr3+) state, not a datable event.
- The colour mechanism partly rests on spectra of synthetic Mg/Cr-doped corundum used to derive cross sections.
- Apparent colour depends on illumination (e.g., D65 vs. A), so real appearance needs stated conditions.
- Naming follows CIBJO (level A).
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
- Orange Sapphire
GB/T 16553—2017 §4.1.17.4 · IMA Mineral List 2026-07 “Corundum”
Construction or treatment status
Natural identity; treatment status unknown
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
Orange Sapphire's material identity has open questions that are not fully settled; this site lists it as "Orange Sapphire" pending further verification.
Evidence
- GB/T · §4.1.17.4
What this means for you
Before buying, check the recommended listing name "Orange Sapphire" 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
- 2026-09-26
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.
Care
Orange 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
- diffusion treatment, irradiation
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Orange sapphire, p.48; §6.2 m (locator checked 2026-09-26)
- 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 toughness; no cleavage
Cleavage
no cleavage
Sources GIA Gem Encyclopedia (care guide)
Treatments and identification leads
Registered treatmentsThe treatments registered for Orange Sapphire are diffusion treatment, heat treatment and irradiation, all with the status treated. Stability and frequencyDiffusion treatment and heat treatment are both stable, and both common on the market; irradiation is unstable, and rare on the market. Values not givenThe identification leads and source clauses for diffusion treatment, heat treatment and irradiation are all marked “—” in the cited source, meaning the cited source gives no value, not “none”.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| diffusion treatmentStatus: treated | commonly | stable | — | — | — |
| heatingStatus: treated | commonly | stable | — | — | — |
| irradiationStatus: treated | rarely | unstable | — | — | — |
Where each treatment acts (schematics): Diffusion-treated · Heated / Heat-treated · Irradiated
“—” means the cited source gives no value for that item, not “none”. Source: CIBJO Gemstone Book 2022
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
VerifyNames, standards, technical facts, clauses and sources
Names
Standard and listing namesThe suggested listing name for Orange Sapphire is Orange Sapphire. The corresponding national-standard name is sapphire (GB/T 16552—2017 Table A.1), and the original GB/T 16552—2017 does not list Orange Sapphire. Trade and mineralogical namesThe mineralogical name is Orange sapphire, referring to a yellowish-orange to reddish-orange gem variety of corundum. Names in four languagesNames are given in Simplified Chinese, Traditional Chinese, English (Orange Sapphire) and Japanese; the wording used by GSJ (Japan) for the Japanese name has not yet been verified, and the Japanese name is only the entry's own. Institution usageOn authority wording, the body with a recorded wording is CIBJO, whose Gemmological Laboratories Book 2024 lists Orange Sapphire; the FTC original documents contain no wording for Orange Sapphire, and this has been checked; the wording of GIA and Gem-A has not yet been verified. The English name shown for bodies without a recorded wording is only the entry's own form and does not represent their position.
- GSJ (Japan) formal name
- オレンジ・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
- Orange sapphire: yellowish orange to reddish orange corundum gem variety
Four-language names
- 简体中文
- 橙色蓝宝石
- 繁體中文
- 橙色藍寶石
- English
- Orange Sapphire
- 日本語
- オレンジ・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 identity; treatment status unknown
What it is and how it's identified
The composition (phase) of Orange Sapphire is corundum, and its body colour is yellowish orange to reddish orange, treatment state untreated; the qualifying note on body colour points out that in chapter 7 of the CIBJO Gemmological Laboratories Book, entries such as fire opal, hessonite and grossular also have orange or orangy colour descriptions. Mohs hardness 9, density 3.95–4.1 g/cm³, refractive index 1.757–1.779 and birefringence 0.008–0.01 take values for sapphire as a whole (all colours and origins), not measurements of Orange Sapphire itself; the density range is derived from the cited clause value of 4.00 for sapphire as a whole with tolerances (+0.10, −0.05), and the refractive index range from the clause value of 1.762–1.770 with tolerances (+0.009, −0.005). Chemical composition, luminescence, UV-visible spectrum, infrared spectrum and magnification are written for sapphire as a whole (all colours and origins); see the material facts on the Sapphire entry.
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 Orange 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 Orange Sapphire (how to read class-level values).
Definition
Orange Sapphire — composition (phase): corundum
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
Durability
Orange 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
For Orange Sapphire, the stability of diffusion treatment is “stable”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- diffusion treatment
- Qualification
This says how well the treatment holds up, not how durable Orange Sapphire itself is.
- General note
- no durability verdict here
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
For Orange Sapphire, the stability of heating is “stable”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- heating
- Qualification
This says how well the treatment holds up, not how durable Orange Sapphire itself is.
- General note
- no durability verdict here
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
For Orange Sapphire, the stability of irradiation is “unstable”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- irradiation
- Qualification
This says how well the treatment holds up, not how durable Orange Sapphire itself is.
- General note
- no durability verdict here
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
Physical properties
Orange 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
Orange 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
Orange 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
Orange Sapphire — body colour: Yellowish orange to reddish orange.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Fire Opal, Hessonite, Grossular and other entries also name orange or an orangish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- 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
For Orange Sapphire in trade, diffusion treatment occurs commonly, heating occurs commonly and irradiation occurs rarely; the status of diffusion treatment, heating and irradiation is treated in each case. The frequency and status of diffusion treatment, heating and irradiation are cited from the Orange sapphire row of the CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022).
How far testing can go
For Orange Sapphire in trade, the reported frequency of diffusion treatment is “commonly”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- diffusion treatment
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
For Orange Sapphire in trade, the reported frequency of heating is “commonly”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- heating
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
For Orange Sapphire in trade, the reported frequency of irradiation is “rarely”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- irradiation
Source & check 2026-09-26
- Source
- 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.
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.
- AQSIQ / SAC (China). GB/T 16553—2017 Gems — Testing.
- SAMR / SAC (China). GB/T 16552—2017 Gems — Nomenclature.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- eCFR (United States). 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.
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 (Orange 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 |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Orange 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.