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Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Sugilite
Also known asLavulite
A silicate mineral species whose mineral name is sugilite. The Chinese market often uses transliterated names for it, and its English trade name is Lavulite. Also known as Lavulite. 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 Sugilite forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify SugiliteHow far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Sugilite2 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing SugiliteCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of SugiliteEach value with its source and check date
- Sugilite 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?
- Name origin and history of SugiliteWhere the name comes from
- Listing and disclosing SugiliteThe listing name to use; what must be disclosed before sale
- Standard clauses that define SugiliteWhich 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
Sugilite is a lithium-bearing ring silicate belonging to the milarite group, with a formula close to KNa2(Fe3+,Mn3+,Al)2Li3Si12O30. It is recognized as a valid mineral species in its own right. Two contrasting geological settings are documented: bedded manganese deposits near Kuruman, South Africa, and a stock of syenite carrying aegirine that intrudes biotite granite on Iwagi Islet, Japan. Rare prismatic crystals aside, it generally appears as compact-to-massive interlocking aggregates of subhedral grains.
Scope: Covers an overview of the origin and occurrence of sugilite as a distinct silicate mineral of the milarite group; does not address synthetic or imitation materials.
Sources Handbook of Mineralogy
Where it forms
A syenite stock carrying aegirine within biotite granite, at Iwagi Islet in Japan; accompanied by albite, aegirine, pectolite, titanite and others
Sources Handbook of Mineralogy
Bedded manganese deposits (Wessels and N'Chwaning mines near Kuruman, South Africa)
Sources Handbook of Mineralogy
How it forms, step by step
K, Na, Li, Fe, Mn, and Si are supplied within an alkaline syenite system or a manganese-rich sedimentary–metamorphic system.
Sources Handbook of Mineralogy
The lithium-bearing ring silicate crystallizes in these settings, forming prismatic crystals (rare).
Sources Handbook of Mineralogy
More commonly it forms interlocking aggregates of subhedral grains, occurring compact to massive.
Sources Handbook of Mineralogy
Link to appearance
Sugilite ranges from light brownish yellow to bright magenta, is nearly colorless in thin section, and has a vitreous luster; its compact, interlocking aggregate habit reflects its crystallization. The source gives no color-cause mechanism.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for sugilite formation.
Sources Handbook of Mineralogy
Supporting findings
Sugilite has been documented at two kinds of locality: a syenite stock rich in aegirine that intrudes biotite granite, on Iwagi Islet in Japan, and bedded manganese deposits close to Kuruman in South Africa.
Evidence grade BScope: Describes known settings; not an exhaustive list of localities.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Wessels and N'Chwaning mines, near Kuruman, Northern Cape, South AfricaG&G (2000) notes declining availability and quality in the 1990s
Sources Gems & Gemology Winter 2000 · Handbook of Mineralogy
Asia
- Iwagi Islet, Ehime, JapanThe original description cited by HoM is from Iwagi Islet
Sources Handbook of Mineralogy
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.
Where the name comes from
Sugilite commemorates the Japanese petrologist Professor Ken-ichi Sugi (1901–1948), the mineral's discoverer.
Evidence grade BScope: This states only the origin of the name and does not establish the material's composition, locality, natural origin, or whether it was treated.
Sources Handbook of Mineralogy
Other research findings
Sugilite is a lithium-bearing ring silicate of the milarite group, with a formula of about KNa2(Fe3+,Mn3+,Al)2Li3Si12O30.
Evidence grade BScope: Describes composition and group affiliation; not an exact composition of a specific specimen.
Sources Handbook of Mineralogy
Sugilite is a species in its own right within the milarite group. Though rare, its crystals are prismatic; more typically the mineral is compact to massive, appearing as interlocking aggregates made up of subhedral grains.
Evidence grade BScope: Defines sugilite's species status and common habit.
Sources Handbook of Mineralogy
Sugilite is named for Professor Ken-ichi Sugi (1901–1948), a Japanese petrologist who discovered the mineral.
Evidence grade BScope: Concerns naming and discovery history, not geological formation.
Sources Handbook of Mineralogy
Sugilite ranges from light brownish yellow to bright magenta, is nearly colorless in thin section, and has a vitreous luster.
Evidence grade BScope: Describes color and luster; the source gives no color-cause mechanism.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source states no absolute geological timescale for sugilite formation.
- The source gives no specific color-cause mechanism for sugilite.
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
- Sugilite (trade names: Sugilite / Royal Azel)
GB/T 16552—2017 Table A.2 “Sugilite”, 5.1.1 a) · CIBJO Gemmological Laboratories Book 2024 §7.2.1.231 “Sugilite”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Filled / Fracture-filled, Dyed
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
Sugilite is Sugilite (KNa2(Fe3+,Mn3+,Al)2Li3Si12O30); use "Sugilite (trade names: Sugilite / Royal Azel)" for listings, and disclose any known treatments.
What this means for you
Before buying, check the recommended listing name "Sugilite (trade names: Sugilite / Royal Azel)" 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.
Care
care (cleaning)2 sources compared
Sugilite — care (cleaning): Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code j
- Treatment state
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Sugilite, p.78; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Sugilite — care (cleaning): ultrasonic and steamer: use caution.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Sugilite row, CLEANING column (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Sugilite — care (special care): colour-improved: normal care, but avoid chemicals.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- treated
- Only after these treatments
- dyeing
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XV, Gemstone Information Chart, Sugilite D, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Sugilite — care (setting): prong and bezel: use caution; channel: use extreme caution; flush and pavé: avoid.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Sugilite row, SETTING column (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Sugilite — care (repair): polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Sugilite row, REPAIR column (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Sugilite — care (display): heat in the display case, sunlight and artificial light: relatively safe.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Sugilite row, DISPLAY column (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.
Common care questions and matching entries
CleaningCleaning Sugilite: the CIBJO Gemstone Book states that, regardless of treatment status, it should not be cleaned ultrasonically. Martin's Gemstone Durability: Design to Display states that for untreated Sugilite, ultrasonic and steam cleaning need caution. Chemicals: the American Gem Trade Association (AGTA) Gemstone Information Manual states that for treated Sugilite, in the case of dyeing only, normal care is enough, but chemicals should be avoided. Repair: Martin's Gemstone Durability: Design to Display states that for untreated Sugilite, polishing needs caution, and the torch, post-soldering pickle and thermal shock should be avoided. Heat and light: Martin's Gemstone Durability: Design to Display states that for untreated Sugilite, heat in a display case, daylight and artificial light are relatively safe. Wear and setting: Martin's Gemstone Durability: Design to Display states that for untreated Sugilite, prong and bezel settings need caution, channel settings need extra caution, and tension and pavé settings should be avoided.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning); ultrasonic and steamer: use caution |
| Heat and thermal shock | polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid |
| Light and display | heat in the display case, sunlight and artificial light: relatively safe |
| Wearing limits (knocks, settings) | prong and bezel: use caution; channel: use extreme caution; flush and pavé: avoid |
Care entries by treatment state
The same entries grouped by the treatment state each applies to; each links to its full wording and source. Letters are CIBJO special-care codes, explained on the gemstone care page.
any treatment state
- care (cleaning) §6.2 j
untreated
- ultrasonic and steamer: use caution
- prong and bezel: use caution; channel: use extreme caution; flush and pavé: avoid
- polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid
- heat in the display case, sunlight and artificial light: relatively safe
treated (Only after these treatments: dyeing)
Treatments and identification leads
Registered treatmentsThe treatments registered for Sugilite are dyeing and filling. Values not givenDyeing has the status colour treated, and filling has the status treated; the cited source gives no stability or prevalence for either dyeing or filling, shown as “—”, which does not mean “none”. Identification cluesDyeing and filling each have their own identification leads, sourced from GB/T 16553—2017.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| dyeingStatus: colour treated | — | — | Treatment | — | See identification leads |
| fillingStatus: treated | — | — | Graded — see §5.4.1, Table 1 | — | See identification leads |
Where each treatment acts (schematics): Dyed · Filled / Fracture-filled
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017; GB/T 16552—2017 Table B.1
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
Besides Sugilite, the name register records "Lavulite", for which no restriction on use as a name is recorded; 3 further names in non-Latin scripts are listed in the name register below (3 with no restriction recorded on use as a name).
Standard and listing namesThe suggested listing name for Sugilite is sugilite (trade names: Sujilite / Shujulai); the English trade name is written Lavulite, not Luvulite; sugilite is the mineral name, and the other two are common market names in Chinese. The corresponding national-standard name is the trade form listed in GB/T 16552—2017 Table A.2, and the mineralogical name is Sugilite. Names in four languagesThe four-language names cover Simplified Chinese, Traditional Chinese, English (Sugilite) and Japanese. Institution usageOn authority wording, the CIBJO Gemmological Laboratories Book 2024 has Sugilite on record; the FTC text on file has no wording for this name (checked); the wording of GIA and Gem-A is not yet verified by this site. Japanese namesThe GSJ (Japan) wording for the entry's own Japanese name is not yet verified by this site. Trade and mineralogical namesIn the name register, Lavulite is an English market name. Candidate search termsA Chinese mineral-name synonym is used only as a candidate search term, based on the GB/T 16552 revision consultation draft (2023, not in force).
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 (4) | ||||
| LavuliteEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| 硅铁锂钠石Simplified Chinese | synonym | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.2; GB/T 16552—2017 Table A.2 “Sugilite”; Note: Draft standard for comment, not in force. |
| 舒俱来Simplified Chinese | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Trade name. |
| 苏纪石Simplified Chinese | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Trade name. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- スギライト／杉石 (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)
- 苏纪石 (GB/T 16552—2017 Table A.2)
- Mineralogical name
- Sugilite (KNa2(Fe3+,Mn3+,Al)2Li3Si12O30)
- Trade names and synonyms
- Lavulite (market name)
Four-language names
- 简体中文
- 杉石（苏纪石）
- 繁體中文
- 杉石（蘇紀石）
- English
- Sugilite
- 日本語
- スギライト／杉石
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Other silicate minerals
- Identity tier
- Mineral species
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T Table B.1Sugilite has filling and dyeing listed in its own row of GB/T 16552—2017 Annex B, Table B.1. Filling improves or changes durability and appearance, with its category defined by grade; dyeing improves or changes colour and is categorised as a treatment. See alsoThe notes to Table B.1 and the grade definitions are on the Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Table B.1, row “Sugilite” (p.17):
This table scrolls sideways on narrow screens.
| Method | Effect | Category |
|---|---|---|
| Filling | Improves or changes durability and appearance | Graded — see §5.4.1, Table 1 |
| Dyeing | Improves or changes colour | Treatment |
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 Sugilite is recorded as sugilite, KNa2Li2Fe2Al(Si12O30)·H2O, and its structure is a crystalline aggregate, usually granular. Mohs hardness is 5.5–6.5 and cleavage none; density is 2.74–2.79 g/cm³, the cited clause giving 2.74 with tolerance +0.05, from which the limits shown are derived. Optic character is anisotropic aggregate, and birefringence not measurable on an aggregate; refractive index 1.61 is the reading commonly obtained by the spot method, a typical value rather than an absolute limit. When untreated, body colour is reddish purple to bluish purple, rarely pink, lustre is waxy to vitreous, pleochroism is not measurable on an aggregate, and fluorescence is usually none. The UV-visible spectrum shows a strong absorption band at 550nm and manganese and iron absorption peaks at 411nm, 419nm, 437nm and 445nm; the infrared spectrum shows the characteristic infrared absorption bands of sugilite in the mid-infrared region.
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
Sugilite — nomenclature status: IMA status A: approved (accepted by the IMA after it was set up in 1958).
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Sugilite — composition (chemistry): sugilite; KNa2Li2Fe2Al(Si12O30) • H2O
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — composition (phase): sugilite
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Sugilite — structure (overall): a crystalline aggregate, typically made up of grains.
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Sugilite — Mohs hardness: 5.5–6.5
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — 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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Sugilite — density: 2.74–2.79 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 2.74, with a stated tolerance of +0.05. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Sugilite — optic character: anisotropic aggregate
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — refractive index: 1.61
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives this as a value commonly read by the spot (distant-vision) method. It is a common value, not an absolute limit.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — birefringence: not measurable on an aggregate
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — transparency: translucent to opaque.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Sugilite — pleochroism: not measurable on an aggregate
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — fluorescence (overall): generally none
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — spectrum (UV-visible): 550 nm strong absorption band; 411 nm absorption peak due to manganese and iron; 419 nm absorption peak due to manganese and iron; 437 nm absorption peak due to manganese and iron; 445 nm absorption peak due to manganese and iron.
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — spectrum (infrared): In the mid-IR, sugilite shows its own diagnostic bands.
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — magnification: granular structure, mineral inclusions
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): §5.2.36 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Sugilite — body colour: Red-purple to bluish purple, rarely pink.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Colour-Change Garnet, Kunzite, Purple Sapphire and other entries also name purple or a purplish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Sugilite — body colour: red-purple and blue-purple, pink (rare)
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
In chapter 5 of GB/T 16553—2017, the colour entries of Taaffeite, Cultured Pearl, Scapolite and other variety clauses also name purple or a purplish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.36 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
How the sources relate
- CIBJO Gemmological Laboratories Book 2024 and GB/T 16553—2017
The two entries agree: reddish purple to bluish purple, and both note that pink is rare.
Quality factors
Sugilite — quality factor (lustre): waxy to vitreous
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): §5.2.36 (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): 1.61 / 2.77; Closest values: 1Larimar 1.62 / 2.82, 2Natural Conch Pearl / Natural Melo Pearl 1.595 / 2.84, 3Prehnite 1.625 / 2.88, 4Aquamarine 1.58 / 2.79, 5Turquoise 1.63 / 2.65
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
Testing and market
Identification leads for dyeing in Sugilite: where the treatment state is colour treated, magnification shows uneven colour distribution, with colourant often concentrated in fissures, between grains or in surface hollows; the dye may give an unusual fluorescence under long- and short-wave UV; and the colour comes off when wiped with solvents such as acetone or absolute ethanol. For filling, where the treatment state is treated, magnification shows filled areas with a lustre different from the host material, and gas bubbles in the filler; under long- and short-wave UV the filled areas often fluoresce differently from the host; the infrared spectrum shows characteristic absorption bands of the filler; and luminescence imaging equipment such as a UV fluorescence viewer can show where the filler lies. The leads for dyeing and filling are cited from GB/T 16553—2017; as to applicability, GB/T 16553—2017 can be followed for Sugilite as a reference only and does not govern it directly. There is no synthetic Sugilite on the market. The tests required by the CIBJO laboratory protocol, and what each method means, are in the protocol table on the laboratory testing page.
The tests the CIBJO laboratory protocol requires for this material, and what each method means, are in the protocol table on the laboratory testing page: §6.1.81.
How far testing can go
Sugilite that has undergone dyeing can be identified by the following features: Under magnification the colour is unevenly distributed and mostly concentrated in fissures, between grains or in surface hollows; the dye may light up with an unusual fluorescence under long- and short-wave UV; wiping with acetone or absolute ethanol can lift the colour.
GB/T 16553—2017
- Treatment state
- colour treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- dyeing
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.36 (dyeing) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite that has undergone filling can be identified by the following features: Under magnification the surface luster of the filled part differs from the host jade and gas bubbles show in the filled area; under long- and short-wave UV the filled part mostly fluoresces differently from the host jade; infrared spectra show characteristic absorption bands of the filler; luminescence imaging (UV fluorescence viewer and similar) shows how the filler is distributed.
GB/T 16553—2017
- Treatment state
- treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- filling
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.36 (filling) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Sugilite — synthetic counterpart on the market: No synthetic counterpart of this material is commercially available
CIBJO Gemstone Book 2022
- Treatment state
- any treatment state
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
Sugilite is defined directly in the CIBJO Gemmological Laboratories Book 2024 under the entry name Sugilite, as the mineral species sugilite with IMA status A; the CIBJO wording is quoted in full under Clause-level definitions on this page. Cross-check result: defined directly by CIBJO; also present in the GB/T annex. The IMA list of minerals entry gives Sugilite, KNa2Fe3+2(Li3Si12)O30, IMA status A and 1974-060, and was cross-checked against the RRUFF/IMA list of minerals main table; the data are public-domain data.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Sugilite | 7.2.1.231 | Red-purple to bluish purple, rarely pink; translucent to opaque | Defined directly by CIBJO; also present in the GB/T annex. |
| Sugilite | IMA Mineral List entry | Sugilite KNa2Fe3+2(Li3Si12)O30 A 1974-060 | Cross-checked against the RRUFF/IMA master mineral list (public domain data). |
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.
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 | Other silicate minerals | Live |
| Treatments recorded for this material | Filled / Fracture-filled, Dyed | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Sugilite 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.