On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Pectolite
A silicate mineral species listed in Annex A.2 of GB/T 16552-2017; the trade name larimar is not a synonym for all pectolite. 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 Pectolite forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify PectoliteHow far lab testing can go and whether a synthetic exists
- Caring for and wearing PectoliteCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of PectoliteEach value with its source and check date
- Pectolite 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 PectoliteWhere the name comes from
- Listing and disclosing PectoliteThe listing name to use; what must be disclosed before sale
- Standard clauses that define PectoliteWhich 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
Pectolite is a triclinic species of the chain silicates whose ideal formula is NaCa2Si3O8(OH). Nepheline syenites host it as a primary mineral, while in cavities within basalts and diabases, and also in serpentinites, peridotites and metamorphosed high-calcium rocks, it appears as a hydrothermal mineral. Acicular, radiating-fibrous or spheroidal aggregates are its usual habit.
Scope: Applies to the genesis and occurrence of natural pectolite as a chain silicate mineral species; does not cover synthetics or artificial imitations.
Sources Handbook of Mineralogy
Where it forms
Nepheline syenites host primary pectolite; cavities in basalt and diabase host the hydrothermal variety; serpentinites, peridotites and metamorphosed lime-rich rocks are further occurrences.
Sources Handbook of Mineralogy
Association: zeolites, datolite, prehnite
Sources Handbook of Mineralogy
How it forms, step by step
An alkaline magma crystallises to nepheline syenite, in which pectolite forms as a primary mineral.
Sources Handbook of Mineralogy
Hydrothermal fluids precipitate pectolite in cavities in basalts and diabases.
Sources Handbook of Mineralogy
Further occurrences include serpentinites, peridotites and high-calcium rocks that have been metamorphosed.
Sources Handbook of Mineralogy
Crystals are acicular or tabular and commonly build radiating fibrous, spheroidal or columnar aggregates.
Sources Handbook of Mineralogy
Link to appearance
Pectolite is mostly colourless, whitish, grayish or yellowish; it has a silky to subvitreous lustre and hardness 4.5-5, is tough when compact (the name alludes to its resistance to pulverization) and may be triboluminescent. Its fibrous, radiating look reflects crystallisation in cavities and fractures.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for pectolite formation.
Sources Handbook of Mineralogy
Supporting findings
In nepheline syenites pectolite is primary; in cavities within diabases and basalts it is hydrothermal; serpentinites, peridotites and metamorphosed high-calcium rocks are further hosts.
Evidence grade BScope: Describes pectolite's multiple natural origins and settings.
Sources Handbook of Mineralogy
Pectolite is associated with zeolites, datolite and prehnite.
Evidence grade BScope: Describes the mineral association.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources name a single or principal locality.
Africa
- Bou Agrao, High Atlas Mountains, Morocco
Sources Handbook of Mineralogy
- Pilanesberg, South Africaprinted as Pilansberg
Sources Handbook of Mineralogy
Asia
- Ahmednagar, Maharashtra, Indiaprinted as Ahmadnagar
Sources Handbook of Mineralogy
Europe
- Monzoni Mountains, Trento, Italyone of Mindat's co-type localities
Sources Mindat: Pectolite
- Sano, Mori, Trento, Italyone of Mindat's co-type localities
Sources Mindat: Pectolite
- Lendalfoot, Ayrshire, Scotland, United Kingdom
Sources Handbook of Mineralogy
- Lovozero and Khibiny massifs, Kola Peninsula, Russia
Sources Handbook of Mineralogy
North America
- Los Checheses, near Baoruco, Barahona, Dominican RepublicApplies to gem blue pectolite (larimar) only; G&G (1989) says all commercial quantities then came from this primary deposit
Sources Gems & Gemology Winter 1989
- Paterson, Passaic County, New Jersey, United States
Sources Handbook of Mineralogy
- Magnet Cove, Arkansas, United States
Sources Handbook of Mineralogy
- Mont Saint-Hilaire, Quebec, Canada
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
Pectolite's English name comes from a Greek word meaning 'compact', alluding to the mineral's resistance to being pulverized.
Evidence grade BScope: The etymology explains the origin of a name only; it does not attest composition, locality, naturalness or treatment.
Sources Handbook of Mineralogy
Other research findings
Pectolite is a triclinic chain silicate species with ideal composition NaCa2Si3O8(OH).
Evidence grade BScope: Species-level composition and crystal-system fact.
Sources Handbook of Mineralogy
Pectolite's name is from the Greek for 'compact', alluding to its resistance to pulverization; it may be triboluminescent and has hardness 4.5-5.
Evidence grade BScope: Concerns naming, physical properties and an optical phenomenon only; not genesis.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source is a mineralogical data sheet and gives no absolute geological timescale for pectolite formation.
- The source does not cover the blue compact fibrous variety known commercially as Larimar; that variety has its own record, and is not described here.
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
- Pectolite
GB/T 16552—2017 Table A.2 “Pectolite” · IMA Mineral List 2026-07 “Pectolite”
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
Pectolite is Pectolite; use "Pectolite" for listings, and disclose any known treatments.
Evidence
- GB/T · Table A.2, row 针钠钙石 (Pectolite)
What this means for you
Before buying, check the recommended listing name "Pectolite" 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
Care
Pectolite — care (heat): Its colour does respond to irradiation and to jeweller's-torch heating; a few seconds under a torch bleached part of a slice, reduced its transparency and introduced small cracks that weaken it.
G&G Winter 1989
- Treatment state
- any treatment state
Source & check 2026-10-06
- Source
- Blue Pectolite from the Dominican Republic: pp. 216, 223, body text (locator checked 2026-10-06)
- Fact checked on
- 2026-10-06
Pectolite — care (light): The authors found the blue colour of blue pectolite to be light-stable; in a test lasting over 50 hours under a fibre-optic lamp, no noticeable colour change was seen.
G&G Winter 1989
- Treatment state
- any treatment state
Source & check 2026-10-06
- Source
- Blue Pectolite from the Dominican Republic: pp. 216, 223, body text (locator checked 2026-10-06)
- Fact checked on
- 2026-10-06
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
Each question links to the matching entries on this page; whether they answer it fully, go by the entry wording.
This table scrolls sideways on narrow screens.
Durability and wearing
Numbers in curly braces, such as {111}, are crystallographic face symbols (Miller indices): each marks a set of crystal faces or cleavage planes. They are reproduced as written in the cited source.
Toughness
Brittle; tough when compact
Cleavage
Perfect on {100} and {001}
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Pectolite, the name register records "Larimar", for which no restriction on use as a name is recorded.
Standard and listing namesThe Chinese formal name for Pectolite is given in GB/T 16552—2017 Table A.2, the mineralogical name is Pectolite, and the suggested listing name is Pectolite. Names in four languagesThe four-language names are given in Simplified Chinese, Traditional Chinese, English (Pectolite) and Japanese (a transliteration and a kanji name); the Japanese GSJ formal name is the transliteration with the kanji name in brackets. Trade and mineralogical namesThe trade name or synonym Larimar refers only to the blue trade variety and is not a synonym for all Pectolite. Institution usageAmong authority wordings, CIBJO lists Pectolite, its wording coming from the CIBJO Gemmological Laboratories Book 2024; the FTC source text has no wording for this name (checked); GIA and Gem-A have not been checked. Bodies without a recorded wording show the English name Pectolite, which does not represent their position.
Name register
Every name recorded for this entry, with how it is classified, whether it may be matched to this entry automatically, whether it may be used as a product name, and the clause it rests on.
This table scrolls sideways on narrow screens.
| Name | Type | Matching | Use as a name | Basis |
|---|---|---|---|---|
| no restriction recorded (1) | ||||
| LarimarEnglish | narrower name (variety or subtype) | matched only once the condition is confirmed | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ペクトライト（ソーダ珪灰石）
- Chinese formal name
- 针钠钙石 (GB/T 16552—2017 Table A.2)
- Mineralogical name
- Pectolite
- Trade names and synonyms
- Larimar (narrower name (variety or subtype); conditional name)
Four-language names
- 简体中文
- 针钠钙石
- 繁體中文
- 針鈉鈣石
- English
- Pectolite
- 日本語
- ペクトライト／ソーダ珪灰石
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
What it is and how it's identified
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
Pectolite — nomenclature status: IMA status G: grandfathered (described before the IMA existed, and generally regarded as a valid species).
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Pectolite — composition (chemistry): Na (Ca>0.5Mn<0.5) 2[Si3O8 (OH) ]
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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — composition (phase): pectolite
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Pectolite — structure (overall): crystalline, or else a crystalline 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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — structure (crystal system): triclinic system
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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — structure (crystal habit): mostly compact needle-like or fibrous aggregates, at times radiating spherulites.
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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Pectolite — Mohs hardness: 4.5–5
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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Pectolite — density: 2.74–2.9 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 2.81, with a stated tolerance of +0.09 / -0.07. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Pectolite — optic character: biaxial positive; usually behaves as an 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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — refractive index: 1.595–1.645
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.599–1.628, with a stated tolerance of +0.017 / -0.004. The range shown here is worked out from that.
- General note
- the clause has finer ranges
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — birefringence: 0.029–0.038
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- General note
- the clause has finer ranges
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — transparency: translucent to opaque.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Pectolite — 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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — fluorescence (overall): none to moderate, green-yellow to orange; short wave is usually stronger than long wave; may be phosphorescent.
GB/T 16553—2017
UV fluorescencegreen-yelloworangenone–moderateDots 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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — spectrum (UV-visible): non-characteristic
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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Pectolite — optical effect (chatoyancy): chatoyancy.
CIBJO Gemmological Laboratories Book 2024
- Qualification
The cited source states that this effect rarely occurs.
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Pectolite — magnification: acicular or fibrous 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): §5.2.39 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Pectolite — body colour: colorless, white or greyish white through yellowish white, green and blue; sometimes a light pinkish red.
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 Pyroxene, Feldspar, Topaz and other variety clauses also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.39 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Pectolite — body colour: light blue, light green, slightly greyish to yellowish white, rarely very light pink.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Sodalite, Aragonite, Pyrophyllite and other entries also name blue or a bluish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
How the sources relate
- GB/T 16553—2017 and CIBJO Gemmological Laboratories Book 2024
Both list greyish to yellowish white, green and blue, and both mention light pink (the CIBJO Gemmological Laboratories Book says very light pink is rare, GB/T 16553—2017 that light pinkish red sometimes occurs). GB/T 16553—2017 also lists colourless and white.
- CIBJO definitions
- chatoyancy
Quality factors
Pectolite — quality factor (lustre): vitreous or silky
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): §5.2.39 (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): 1.62 / 2.82; Closest values: 1Prehnite 1.625 / 2.88, 2Sugilite 1.61 / 2.77, 3Giant Clam Shell 1.605 / 2.79, 4Achroite 1.635 / 2.86, 5Dushan Yu / Dushan Jade 1.63 / 2.9
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
Which tests the CIBJO laboratory protocol requires for Pectolite, and what each method means, are set out in the protocol table on the laboratory testing page. The note on testing methods in the CIBJO laboratory protocol mentions that the special optical effect of Pectolite is the cat's-eye effect, and that the cat's-eye effect is rare. According to CIBJO, no synthetic counterpart of Pectolite is on the market.
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: §6.1.57.
How far testing can go
Pectolite — 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
Pectolite — notes on test methods in the CIBJO laboratory protocol:
| Test method | What the protocol notes for it |
|---|---|
| Phenomena: | Cat’s eye (rare) |
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- any treatment state
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.
Clause-level definitions
Pectolite has a direct definition in the CIBJO Gemmological Laboratories Book 2024, recorded as Pectolite; the definition states that Pectolite is the mineral species pectolite, IMA status G, with the CIBJO wording quoted in full under Clause-level definitions on this page. The cross-check result is: defined directly by CIBJO, and also appears in the GB/T annex. The IMA Mineral List entry records it as Pectolite NaCa2Si3O8(OH) G 1828, cross-checked against the RRUFF/IMA master mineral list, using public domain data.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Pectolite | 7.2.1.172 | light blue, light green, slightly greyish to yellowish white, rarely very light pink, translucent to opaque; may show chatoyancy see Larimar | Defined directly by CIBJO; also present in the GB/T annex. |
| Pectolite | IMA Mineral List entry | Pectolite NaCa2Si3O8(OH) G 1828 | 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.
- 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.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Other silicate minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Pectolite 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.