On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Trade name: geographic / origin-linked name · Natural identity; treatment status unknown
Larimar
Also known asBlue pectolite
A trade name for blue to blue-green pectolite; the basic mineral name is Pectolite, and larimar itself is not a separate mineral species. 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.
Questions people ask about Larimar
Every sentence below is followed by the registered fact it rests on; answers add no new facts and promise no outcome.
Q1Is larimar a real gemstone, and what is it made of?
Larimar is a trade name for blue pectolite rather than a separate mineral species; the mineral it is made of is pectolite.G&G Winter 1989 · G&G Summer 2020It comes from altered basalt at a single volcanic deposit around Barahona in the Dominican Republic.G&G Winter 1989
Q2How can you tell real larimar from imitations?
Standard gemmological tests such as microscopy, refractive index and specific gravity should be enough: a ceramic imitation gave a spot refractive index of 1.53 and a specific gravity of 1.87, distinctly lower than larimar's.G&G Spring 2013Larimar's refractive index is recorded as 1.595–1.645.GB/T 16553—2017Its density is recorded as 2.74–2.9 g/cm³.GB/T 16553—2017Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer
Q3Does larimar fade in the sun?
Its blue was found to be light-stable: in a test of over 50 hours under a fibre-optic lamp, no noticeable colour change was seen.G&G Winter 1989Heat is a different matter: a few seconds under a jeweller's torch bleached part of a slice, reduced its transparency and introduced small cracks.G&G Winter 1989
Q4Is larimar durable enough for everyday wear?
Larimar's Mohs hardness is recorded as 4.5–5.GB/T 16553—2017Pectolite, the mineral it is made of, is brittle and tough only when compact.Handbook of MineralogyIt also has perfect cleavage.Handbook of MineralogyEven a few seconds of jeweller's torch heat introduced small cracks that weaken it.G&G Winter 1989
Q5Why is larimar blue?
Its blue is attributed to trace copper (Cu2+), but the copper content is very low, about 46–47 ppm, and the colouring mechanism is not well understood.G&G Winter 1989 · G&G Summer 2020Its body colour is blue to blue-green, mottled with white.CIBJO Gemmological Laboratories Book 2024
What this page can answer
This page covers
- How Larimar 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 LarimarIdentification points from the research literature; how far lab testing can go
- Caring for and wearing LarimarCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of LarimarEach value with its source and check date
- Larimar 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 LarimarWhere the name comes from
- Listing and disclosing LarimarThe listing name to use; what must be disclosed before sale
- Standard clauses that define LarimarWhich 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
Larimar is a trade name for blue pectolite, whose parent material is the chain-silicate mineral pectolite. It is a hydrothermal mineral filling veins and cavities within altered basalt at a single volcanic deposit near Barahona in the Dominican Republic; that basalt is strongly weathered and mostly converted to fine-grained serpentine. Its blue colour is attributed to trace Cu2+ in the structure. The formation content here rests on the hydrothermal occurrence of the parent mineral pectolite; the general formation of the parent is not recast as a formation unique to the trade name, and the trade name is not equated with a mineral species.
Scope: Covers an overview of the occurrence and origin of larimar (blue pectolite) and its parent mineral pectolite; the origin follows that of the parent mineral, and no independent mineralisation process is claimed for this trade name.
Sources G&G Winter 1989 · G&G Summer 2020
Where it forms
The single volcanic deposit around Barahona province, Dominican Republic; blue pectolite occurs in cavities and veins of altered (SERPENTINIZED) basalt.
Sources G&G Winter 1989
Pectolite forms primarily in nepheline syenite; hydrothermal occurrences include basalt cavities, serpentinite and peridotite.
Sources Handbook of Mineralogy · G&G Winter 1989
How it forms, step by step
A basaltic intrusion is emplaced and cools, then is intensely weathered and altered to fine-grained serpentine.
Sources G&G Winter 1989
Copper-bearing hydrothermal fluids migrate through cavities and veins in the basalt and crystallize blue pectolite.
Sources G&G Winter 1989 · Handbook of Mineralogy
Pectolite is associated with natrolite, calcite, and hematite; on weathering it is exposed and waterworn fragments are transported downstream into alluvials.
Sources G&G Winter 1989
Link to appearance
The sources attribute the blue colour to trace Cu2+ while noting the very low copper content and an unclear colouring mechanism; appearance and colour alone cannot prove origin, naturalness, or treatment.
Sources G&G Winter 1989 · G&G Summer 2020
Timescale
The sources in this record give no absolute age or growth duration for Larimar/pectolite.
Sources G&G Winter 1989 · G&G Summer 2020
Related base materials
- pectolite: Larimar is the trade name/blue variety name for blue pectolite; its parent material is the mineral species pectolite
Supporting findings
Blue pectolite (Larimar) is a hydrothermal mineral found in veins and cavities within the altered basalt — that is, it grew from hydrothermal fluids inside cavities in basalt.
Evidence grade AScope: Applies to the mode of occurrence of blue pectolite (hydrothermal filling of cavities/veins in basalt); does not claim it is a species.
Sources G&G Winter 1989
Larimar comes from altered basalt within a single volcanic deposit (around Barahona, Dominican Republic); waterworn fragments were first found in the Rio Baoruco alluvials and traced upstream to the in-situ source.
Evidence grade AScope: Describes the single-deposit setting and mode of occurrence; no detailed genetic mechanism.
Sources G&G Winter 1989
Pectolite is a primary constituent of nepheline syenite; hydrothermally it fills cavities in basalt and diabase, occurs in serpentinite and peridotite, and is found in metamorphosed calcium-rich rocks.
Evidence grade BScope: Describes the diversity of pectolite occurrences; not specific to the Dominican blue variety.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources name a single or principal locality.
North America
- Los Checheses, near Baoruco, Barahona, Dominican RepublicG&G (1989) states the blue pectolite occurs in a single volcanic deposit of about 0.15 km²
Sources G&G Winter 1989
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
The blue colour of Larimar is attributed to trace copper (Cu2+) in its structure; copper content is very low (about 46–47 ppm) and the colouring mechanism is not well understood.
Evidence grade AScope: Stated conservatively as 'believed/related to', not a confirmed quantitative colour model.
Sources G&G Winter 1989 · G&G Summer 2020
Where the name comes from
Larimar is a trade name for blue pectolite. The parent mineral name pectolite is Greek, meaning "compact", a reference to how hard it is to reduce the mineral to powder; that is not the source of the trade name. "Larimar" itself was coined by Mendez from his daughter's nickname Lari combined with the Spanish word for sea, mar, replacing the earlier trade name Travelina.
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. The etymology belongs to the parent mineral name and is not the origin of the trade or variety name itself.
Sources Handbook of Mineralogy · G&G Winter 1989
How it is identified
A ceramic imitation of larimar gave a spot refractive index of 1.53 and a specific gravity of 1.87, distinctly lower than larimar's; standard gemmological tests such as microscopy, refractive index and specific gravity should be enough to tell them apart.
Evidence grade AScope: Based on one ceramic imitation reported in Gems & Gemology; glass or resin imitations are not covered, and the tests need instruments.
Sources G&G Spring 2013
Other research findings
'Larimar' is a trade name and blue-variety name for blue pectolite, not an independent mineral species; its parent material is the mineral pectolite (NaCa2Si3O8(OH)).
Evidence grade AScope: Defines the trade name relative to its parent species; it does not authenticate any specimen's origin or naturalness.
Sources G&G Winter 1989 · G&G Summer 2020
The ideal chemical formula of pectolite is NaCa2Si3O8(OH).
Evidence grade BScope: A mineralogical composition fact only; no genetic implication.
Sources Handbook of Mineralogy
In a Gems & Gemology study of blue pectolite (larimar), a piece kept under a FiberLite lamp for more than 50 hours showed no noticeable colour change against an unexposed control, whereas brief exposure to a jeweller's torch turned pectolite whiter as small cracks spread through it.
Evidence grade AScope: Reports one laboratory test of colour stability under light and torch heat; it is not cleaning or care advice, and no authoritative cleaning guidance for larimar was found.
Sources G&G Winter 1989
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- Larimar is a trade name, not an independent species; its formation content rests on the parent mineral pectolite.
- The blue colouring mechanism is stated conservatively (Cu2+).
- No absolute age or growth duration is 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
- Larimar (blue pectolite)
GB/T 16552—2017 5.1.1 c) · CIBJO Gemmological Laboratories Book 2024 §7.2.1.129 “Larimar”
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
"Larimar" is a market name rather than a mineral species name; before using it, verify: Industry-wide term that does not denote a single species.
Evidence
- CIBJO · 7.2.1.129
What this means for you
Before buying, check the recommended listing name "Larimar (blue pectolite)" 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
- Industry-wide term that does not denote a single species.
- Suggested listing name
- Larimar (blue pectolite)
Care and wear
Care
Larimar — 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
Larimar — care (light): The authors found the blue colour of larimar (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.
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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 Larimar, the name register records "Blue pectolite", for which no restriction on use as a name is recorded; one further name in a non-Latin script is listed in the name register below (1 with no restriction recorded on use as a name).
Recommended listing nameThe suggested listing name for Larimar is Larimar (blue pectolite). Trade and mineralogical namesLarimar is a trade name; the mineralogical name is Blue pectolite, that is, pectolite. Chinese standard nameUnder GB/T 16552—2017 Table A.2 its naming counterpart is pectolite, and GB/T 16552—2017 does not list the name Larimar. Trade and mineralogical namesThere is a Chinese market name meaning sea-pattern stone and the English synonym Blue pectolite; both are recorded on the basis of this site's own ruling, without a clause reference. Names in four languagesThe four-language names are the Simplified Chinese name, the Traditional Chinese name, the English name Larimar and the Japanese name. Institution usageOn authority wording, CIBJO lists Larimar (CIBJO Gemmological Laboratories Book 2024); the FTC text on file has no wording for this name (checked); GIA and Gem-A are unchecked, and the name shown does not represent the position of the bodies concerned. Japanese namesA Japanese name is recorded, and the wording of GSJ (Japan) for this name is not yet verified by this site.
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.
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| Name | Type | Matching | Use as a name | Basis |
|---|---|---|---|---|
| no restriction recorded (2) | ||||
| Blue pectoliteEnglish | synonym | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| 海纹石Simplified Chinese | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ラリマー (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)
- 针钠钙石 (GB/T 16552—2017 Table A.2)
- Mineralogical name
- Blue pectolite; Larimar is a trade name
- Trade names and synonyms
- Blue pectolite (synonym)
Four-language names
- 简体中文
- 拉利玛
- 繁體中文
- 拉利瑪
- English
- Larimar
- 日本語
- ラリマー
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
- Trade name: geographic / origin-linked name
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
Larimar is composed of pectolite (phase); its body colour is blue to bluish green with white mottling, for untreated material; in Chapter 7 of CIBJO, the colour descriptions of entries such as amazonite, common opal and lazulite also mention blue or bluish tones; transparency is translucent to opaque. The other facts are taken for pectolite (the whole mineral species), not measured for Larimar on its own: overall structure crystalline or a crystalline aggregate, triclinic, usually as dense acicular or fibrous aggregates, sometimes as radiating spherulitic aggregates; Mohs hardness 4.5–5; density 2.74–2.9 g/cm³, from the clause value 2.81 with tolerance +0.09/−0.07, from which the limits are derived; optic character biaxial, positive, commonly an anisotropic aggregate; refractive index 1.595–1.645, from the clause value 1.599–1.628 with tolerance +0.017/−0.004, from which the limits are derived, the clause having finer ranges, with the overall value used.
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, magnification: these whole-class features are given in the cited clause for pectolite (the whole mineral species), so they are not repeated on the Larimar page; see the material facts on the Pectolite entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Larimar (how to read class-level values).
Definition
Larimar — composition (phase): pectolite
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Larimar — structure (overall): crystalline, or else a crystalline aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
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
Larimar — structure (crystal system): triclinic system
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
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
Larimar — 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
- What this covers
- pectolite (the whole mineral species)
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
Durability
Larimar — 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
- What this covers
- pectolite (the whole mineral species)
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
Physical properties
Larimar — density: 2.74–2.9 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
- 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 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.39 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Larimar — optic character: biaxial positive; usually behaves as an anisotropic aggregate.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
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
Larimar — refractive index: 1.595–1.645
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
- 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 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.39 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Larimar — birefringence: 0.029–0.038
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
- General note
- the clause has finer ranges
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
Larimar — transparency: translucent to opaque.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Larimar — pleochroism: not measurable on an aggregate
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
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
Larimar — body colour: Blue to blue-green, mottled with white.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Amazonite, Common Opal, Lazulite 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
Quality factors
Larimar — quality factor (lustre): vitreous or silky
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- pectolite (the whole mineral species)
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
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
The CIBJO laboratory protocol covers Larimar under “Pectolite” (§6.1.57): see identification on the Pectolite entry; the required tests are listed on the CIBJO laboratory protocol table for Pectolite.
How far testing can go
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
Larimar has a direct clause-level definition in the CIBJO Gemmological Laboratories Book 2024 under the entry name Larimar; the text records larimar as the mineral species pectolite with the trade name larimar, and the CIBJO wording is quoted in full under Clause-level definitions on this page. Cross-check result: defined directly by CIBJO; the same English name was not found directly in the GB/T annex of this edition.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Larimar | 7.2.1.129 | Blue to blue-green, mottled with white, translucent to opaque pectolite | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
Evidence and sources
Authority basis and clause sources
Sources
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.
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| 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 Larimar 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.