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Artificial products / Manufactured products · Artificial product type · Synthetic product
Synthetic Alexandrite
Synthetically made colour-change Chrysoberyl, the counterpart of natural Alexandrite; GB/T 16552-2017 Annex A Table A.4 lists it as "synthetic alexandrite". 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 Synthetic Alexandrite 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 Synthetic AlexandriteIdentification points from the research literature
- Hardness, density and refractive index of Synthetic AlexandriteEach value with its source and check date
- Synthetic Alexandrite in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name, names in national standards; and: Has any of GIA, FTC, CIBJO or Gem-A put a name for it on record here?
- Listing and disclosing Synthetic AlexandriteThe listing name to use; what must be disclosed before sale
- Standard clauses that define Synthetic AlexandriteWhich 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
Synthetic alexandrite is colour-change chrysoberyl (BeAl2O4) crystallised by humans in a laboratory to correspond to natural alexandrite, not a product of natural geological ore formation. In CIBJO's terms, a synthetic is made by people yet matches the natural gem in chemistry, physical properties and structure to all intents; growth may follow the route of growing Ti3+-doped crystals in neutral/reducing atmospheres with subsequent oxygen annealing to precipitate TiO2, or use the floating-zone technique (e.g. the Seiko Epson patent for cat's-eye alexandrite with tubular fluid inclusions), with colouring elements introduced to give colour change, and without the metamorphic/pegmatitic ore-forming processes required for natural alexandrite.
Scope: Applies to explaining the artificially grown nature of synthetic alexandrite and its naming boundaries; not used to describe the genesis of natural alexandrite deposits.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Where it forms
Controlled laboratory environment: artificial crystal growth (including annealing) under controlled temperature and atmosphere, not a natural geological setting.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Growth mode: melt/solution or floating-zone growth with colouring elements to reproduce the alexandrite colour change.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
How it forms, step by step
Prepare Be- and Al-bearing feedstock doped with colouring elements to produce colour change.
Grow the synthetic crystal by melt/solution growth or floating-zone technique under a controlled (neutral/reducing) atmosphere.
If required, anneal in oxygen so TiO2 needles exsolve (for cat's-eye/star material).
The whole process is man-made with no natural ore formation; the product must be named and disclosed as e.g. 'synthetic alexandrite'.
Link to appearance
Because synthetic alexandrite shares the composition and structure of natural alexandrite and requires added chromophores for the colour change, its appearance is essentially the same; floating-zone cat's-eye alexandrite may contain tubular fluid inclusions, a potential identification clue.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Timescale
The selected authorities give no growth or annealing duration for synthetic alexandrite.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Related base materials
- Alexandrite (colour-change chrysoberyl): synthetic-counterpart | Synthetic alexandrite is the laboratory-grown counterpart of alexandrite
- Chrysoberyl (BeAl2O4): mineral-host | The parent mineral is likewise chrysoberyl
Supporting findings
A floating-zone technique, capable of producing tubular fluid inclusions, can be used to grow cat's-eye synthetic alexandrite; the Seiko Epson Corporation of Japan holds the patent on this method.
Evidence grade AScope: Specific to the patented cat's-eye alexandrite route, not all synthetic alexandrite.
An artificial route to chatoyant or star synthetic chrysoberyl, alexandrite-type material included, is to grow Ti3+-doped crystals under neutral or reducing conditions and then anneal them in oxygen, precipitating TiO2.
Evidence grade AScope: The route targets chatoyant/star material; colour change itself additionally depends on added chromophores.
Causes of colour and optical effects
The alexandrite effect arises because transition-metal chromophores—chiefly chromium ions in alexandrite-type material—produce absorption bands toward both ends of the visible spectrum, leaving transmission windows in between; because light sources differ in spectral make-up, the mix of transmitted wavelengths shifts and so does the colour. Daylight, richer in blue-green, leaves a greener transmission, while an incandescent lamp, richer in orange-red, leaves a redder or purpler one.
Evidence grade AScope: The mechanism is drawn from quantitative work on chromophore absorption and illuminant spectra in corundum and garnet and represents the general principle of colour change; assigning it to alexandrite-type material rests on the general model and does not establish locality, natural origin, or treatment of any particular sample.
Synthetic alexandrite is a laboratory-grown counterpart sharing the chrysoberyl (BeAl2O4) host and essential physical properties of natural alexandrite; its colour change depends on deliberately introduced chromophores and follows the same principle as the natural stone—absorption bands responding to the spectrum of the illuminant—while artificial growth itself does not alter this optical mechanism.
Evidence grade AScope: The claim applies the general principle of colour change to synthetic alexandrite; it neither describes a specific growth process nor establishes locality, natural origin, or treatment of any particular sample.
How it is identified
Synthetic alexandrite can look very close to the natural stone and cannot be separated by the unaided eye. Naming rules require laboratory-grown material to be labelled, but that is a labelling rule rather than a means of identification; confirming natural versus synthetic, or detecting composite and imitation material, relies on laboratory chemical and spectroscopic testing. The verdict should be issued by a qualified gem laboratory.
Evidence grade BScope: A conservative call: the listed sources give no material-specific tests, only that appearance is unreliable and laboratory testing is needed.
Sources CIBJO Gemstone Book 2022
Other research findings
Alexandrite is the colour-change gem variety of chrysoberyl (BeAl2O4); synthetic alexandrite is its laboratory-grown counterpart.
Evidence grade AScope: Defines the host mineral of alexandrite; carries no provenance information.
In CIBJO's terms, a synthetic has to match the natural gem in chemistry, physical properties and structure to all intents, and must be named and disclosed as 'synthetic' or 'laboratory-grown' followed by the name of the natural gem.
Evidence grade AScope: A classification/naming rule; not a specific growth process.
Sources CIBJO Gemstone Book 2022
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The routes given concern mainly cat's-eye/star and floating-zone material and do not cover all synthetic alexandrite processes.
- No temperature, duration or equipment parameters for growth/annealing are given.
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
- Synthetic Alexandrite
GB/T 16552—2017 Table A.4 “Synthetic Alexandrite” · CIBJO Gemstone Book 2022 4.3.3.1
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
"Synthetic Alexandrite" is a market name rather than a mineral species name; before using it, verify: Not a mineral: man-made or non-mineral material.
Evidence
- GB/T · Table A.4, row 合成变石 (Synthetic Alexandrite)
What this means for you
Before buying, check the recommended listing name "Synthetic Alexandrite" 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
- Not a mineral: man-made or non-mineral material.
- Suggested listing name
- Synthetic Alexandrite
VerifyNames, standards, technical facts, clauses and sources
Names
Standard and listing namesThe Chinese formal name for Synthetic Alexandrite comes from GB/T 16552—2017 Table A.4, and the suggested listing name is also Synthetic Alexandrite. Names in four languagesThe four-language names are given in Simplified Chinese, Traditional Chinese, English (Synthetic Alexandrite) and Japanese, the Japanese form being the Japanese GSJ formal name; the mineralogical name is described in English as synthetic colour-change chrysoberyl corresponding to alexandrite. National standard namesGermany (RAL) writes Synthetischer Alexandrit and the EU Synthetic Alexandrite. Institution usageAmong authority wordings, the FTC and CIBJO source texts have no wording for this name (checked), and GIA and Gem-A have not been checked; bodies without a recorded wording show the entry's own English name, which does not represent their position.
- GSJ (Japan) formal name
- 合成アレキサンドライト
- Chinese formal name
- 合成变石 (GB/T 16552—2017 Table A.4)
- Mineralogical name
- Synthetic colour-change chrysoberyl corresponding to alexandrite
Four-language names
- 简体中文
- 合成变石
- 繁體中文
- 合成變石
- English
- Synthetic Alexandrite
- 日本語
- 合成アレキサンドライト
National and regional formal names
- Germany (RAL)
- Synthetischer Alexandrit
- European Union
- Synthetic Alexandrite
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Artificial products / Manufactured products
- Material domain
- Artificial products / Manufactured products
- Browsing family
- Synthetic gem products
- Identity tier
- Artificial product type
- Mineral chemical class
- Mixed / composition-dependent
- Construction or treatment status
- Synthetic product
What it is and how it's identified
The material facts for Synthetic Alexandrite are registered from GB/T 16553—2017 Gems — Testing: composition BeAl2O4; the structure is crystalline and orthorhombic, with a short prismatic crystal habit; Mohs hardness 8.5, no cleavage, and this site notes that hardness alone is not enough to judge durability; density 3.71–3.75 g/cm³, derived from the clause value of 3.73 with a tolerance of ±0.02; the optic character is anisotropic, biaxial positive, refractive index 1.74–1.759, derived from the clause value of 1.746–1.755 with a tolerance of +0.004/−0.006, and birefringence 0.008–0.01. When untreated, pleochroism is strong, in green, orange and purplish red, the lustre is vitreous to subadamantine, and the body colour is bluish green in daylight, changing to brownish red to purplish red under incandescent light; the cat's-eye effect and the colour-change effect can be seen. This site notes that the colours GB/T 16553—2017 lists for alexandrite overlap with the body colour of Synthetic Alexandrite.
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”.
Definition
Synthetic Alexandrite — composition (chemistry): BeAl2O4
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Structure
Synthetic Alexandrite — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — structure (crystal system): orthorhombic
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — structure (crystal habit): short-columnar
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Synthetic Alexandrite — Mohs hardness: 8.5
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
- General note
- hardness only, not durability
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Synthetic Alexandrite — density: 3.71–3.75 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.73, with a stated tolerance of ±0.02. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Synthetic Alexandrite — optic character: biaxial, optically positive (anisotropic)
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — refractive index: 1.74–1.759
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.746–1.755, with a stated tolerance of +0.004 / -0.006. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — birefringence: 0.008–0.01
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — pleochroism: strong, green, orange and purple-red
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — fluorescence (overall): moderate to strong, red
GB/T 16553—2017
UV fluorescenceredmoderate–strongDots are illustrative colours built from the colour names, not measured values
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — spectrum (UV-visible): 680 nm strong absorption peak; 678 nm strong absorption peak; 665 nm weak absorption peak; 655 nm weak absorption peak; 645 nm weak absorption peak; 580~630 nm partial absorption; 476 nm weak absorption peak; 473 nm weak absorption peak; 468 nm weak absorption peak; absorption in the violet region.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — spectrum (infrared): Chrysoberyl's Be-O and Al-O vibrations produce the diagnostic mid-IR bands; the synthetic alexandrite's functional-group-region bands depart from those of natural chrysoberyl.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-22
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-22)
- Fact checked on
- 2026-09-22
Synthetic Alexandrite — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — optical effect (colour change): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — magnification: flux method: veil-like, gauzy inclusions, leftover flux, platelets of platinum, straight, parallel growth striations; pulling method: needle inclusions, curved growth striations; zone melting method: bubble, vortex structure.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Synthetic Alexandrite — body colour: colour change: blue-green by daylight, brown-red to purple-red by incandescent light.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
The colours GB/T 16553—2017 lists for Alexandrite overlap with this entry: blue-green in daylight and brownish red to purplish red in incandescent light.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- chatoyancy, colour change
Quality factors
Synthetic Alexandrite — quality factor (lustre): vitreous to subadamantine
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.7 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
This material (RI / SG midpoints): 1.749 / 3.73; Closest values: 1Cobalt Spinel 1.723 / 3.63, 2Grossular 1.745 / 3.9, 3Malachite 1.782 / 3.67, 4Rhodolite 1.755 / 3.9, 5Benitoite 1.78 / 3.65
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
Clause-level definitions
Synthetic Alexandrite has a clause-level definition in GB/T 16552—2017 Annex A under the entry Synthetic Alexandrite, defined as synthetic colour-change chrysoberyl corresponding to alexandrite. The cross-check result for this definition is that GB/T lists it directly, and no CIBJO entry under the same standalone heading was found; the naming clauses for synthetic gems are also in the CIBJO Gemstone Book 2022.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Synthetic Alexandrite | GB/T 16552-2017 Annex A | Synthetic colour-change chrysoberyl corresponding to alexandrite | Listed directly by GB/T; CIBJO carries no standalone entry under the same name. |
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.
- Federal Trade Commission (United States). In the Loupe: Advertising Diamond, Gemstones and Pearls.
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 | Synthetic gem products | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Synthetic Alexandrite 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.