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UnderstandWhat it is, what people ask, how far this page goes
Natural organic and biogenic materials · Organic or biogenic material · Natural identity; treatment status unknown
Keshi Cultured Pearl
Also known asAkoya Keshi cultured pearl · Keshi pearl (not to be used as a name) · Keshi Saltwater Cultured Pearl · South-sea keshi cultured pearl · Tahitian keshi cultured pearl
A pearl without a nucleus that forms as a by-product of pearl culturing. It is not a natural pearl, and when called "pearl" it must carry the word "cultured". 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 Keshi Cultured Pearl forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify Keshi Cultured PearlIdentification points from the research literature
- Treatments and enhancements of Keshi Cultured PearlThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Keshi Cultured PearlCleaning, heat, chemicals and light, as the cited sources give them
- Hardness and refractive index of Keshi Cultured PearlEach value with its source and check date
- Keshi Cultured Pearl 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 Keshi Cultured PearlThe listing name to use; what must be disclosed before sale
What we cannot conclude
- Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.
- Geographic origin, unless an origin report accompanies the item.
- Price, rarity or investment value: this wiki covers naming and disclosure only.
Material research: formation, causes and history
What authoritative sources say about how this material forms, what causes its colour and optical effects, where its name comes from and how people have used it. Each statement carries an evidence grade and its sources; it describes the material in general, not any specific piece.
How it forms
Keshi pearls are non-bead cultured pearls (NBC) produced as a by-product of bead-culture operations, sometimes called 'keshi' in the trade. They are mainly composed of solid nacre, like natural pearls. Several pathways produce them: if the grafted mantle tissue separates from the bead, the tissue can still secrete nacre and form a pearl sac, yielding an NBC pearl; if the bead is ejected and an existing or partially formed pearl sac continues to secrete nacre, an NBC pearl forms; and individual epithelium cells that break away from the main mantle tissue can form additional accidental pearl sacs. NBC pearls may appear as individual pearls or as attached growths on bead cultured pearls ('Tokki pearls') that later detach.
Scope: Applies to explaining the origin and internal structure of non-beaded cultured pearls (known in the trade as keshi); 'keshi' is a trade term and should be used only in the qualified form 'keshi cultured pearl'.
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
Where it forms
Saltwater or freshwater farms, in the host gonad or mantle area, as a by-product of bead culture.
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
Within mantle tissue detached from the bead or within accidentally formed pearl sacs.
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
How it forms, step by step
During a bead-culture operation, the grafted mantle tissue separates from the bead (or the bead is ejected).
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
The separated tissue continues to secrete nacre and forms a pearl sac, or the existing sac keeps secreting nacre after bead ejection.
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
(Alternate route) Individual epithelium cells break away from the main mantle tissue and form additional/accidental pearl sacs.
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
The solid nacre secreted by the sac forms an NBC pearl, either an individual or a surface growth on a bead cultured pearl (Tokki).
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
Link to appearance
NBC pearls are often irregular/baroque in shape; internally they may show organic-rich concentric, void and linear structures used to separate them from natural pearls, though this is not always conclusive.
Sources CIBJO Pearl Book 2024 · G&G Fall 2021 · G&G Fall 2024
Timescale
The available sources give no growth duration or age for keshi (NBC) pearls.
Sources G&G Fall 2024
Related base materials
- Cultured pearl: byproduct-of-cultured-pearl | A beadless by-product of bead-nucleated cultured pearl production, often called a non-bead cultured pearl (NBC)
Supporting findings
Non-bead cultured pearls (keshi) are by-products of bead cultured pearl cultivation, mainly composed of solid nacre, similar to natural pearls.
Evidence grade AScope: Definitional description of NBC pearls; 'keshi' is a trade term.
Sources CIBJO Pearl Book 2024 · G&G Fall 2024 · G&G Fall 2021
An NBC pearl can form when the grafted mantle tissue separates from the bead, or when the pearl sac continues to secrete nacre after the bead is ejected.
Evidence grade AScope: Mechanism from anatomical study of bead-culture operations, covering first and later operations.
Recorded localities
This is an organic material; its localities are the harvest or culture areas (waters or species ranges) recorded by authoritative sources.
Oceania
- French PolynesiaTahitian keshi only (by-product of black-lip culture); other keshi follow their farms
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
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 the origin determination guide and the overview of recorded localities.
How it is identified
Keshi pearls resemble natural pearls, and materials that look similar cannot be assigned an origin or category by eye alone. Determination relies on laboratory testing such as real-time X-radiography, real-time microradiography for nacre thickness, UV-visible reflectance spectroscopy, X-ray fluorescence, and computed micro-tomography (μCT) for loose pearls. Pearl origin and category must be judged by an accredited laboratory, and this entry provides no self-identification method or threshold.
Evidence grade AScope: Appearance is insufficient to settle origin and category; determination requires testing by an accredited laboratory, and this entry gives no self-test method or threshold.
Sources GIA: How GIA Identifies Pearls · CIBJO Pearl Book 2024
Other research findings
CIBJO states that using 'keshi' alone is misleading and inappropriate and recommends a qualified term such as 'keshi cultured pearl'; GIA does not use the term on pearl reports.
Evidence grade AScope: Terminology-standard boundary; does not change the fact that the material is an NBC pearl.
NBC pearls commonly show three internal structural types—organic-rich concentric, void and linear—used to distinguish them from natural pearls, though identification is not always conclusive.
Evidence grade AScope: Structural criteria from laboratory research; some samples overlap with natural-pearl structures, causing inconclusive results.
NBC pearls can be semi-baroque and irregular in shape, and a multicore NBC pearl from P. maxima has been documented.
Evidence grade AScope: A single-sample case record; not representative of all NBC pearl shapes.
CIBJO's Pearl Book 2024 defines a Keshi cultured pearl (5.106) as a trade term for a non-beaded cultured pearl, one that arises — whether deliberately or by accident, through human intervention — in marine pearl oysters including the Akoya, the Silver/Gold-lipped and the Black-lipped oysters, and that is a by-product of cultivation; the book advises against using the bare word 'Keshi' (5.105), which must instead be qualified as 'keshi cultured pearl'.
Evidence grade AScope: Naming definition and terminology rule per CIBJO 5.106/5.105.
Sources CIBJO Pearl Book 2024
Pearl quality is usually assessed through lustre, nacre thickness, surface, shape, colour and matching (GIA summarises the pearl value factors as seven: size, shape, colour, nacre, lustre, surface and matching). Keshi cultured pearls are non-bead cultured pearls formed inside the pearl sac and are usually irregular in shape, so their evaluation does not apply a 'round' standard and instead emphasises the strength of lustre, the cleanliness of the surface, the saturation of colour and the overall distinctive form; Keshi pearls with fine lustre and a clean surface are likewise prized in strands and in jewellery design. With no bead nucleus, nacre thickness over a nucleus is not the focus of evaluation. Category and any treatment must be determined by an accredited laboratory through testing.
Evidence grade AScope: This describes the pearl quality characteristics the market generally prizes; it is not a grade for any specific specimen and is neither price nor investment advice; pearl category (natural or cultured) and any treatment must be determined by an accredited laboratory on the specific specimen.
Sources GIA: How GIA Identifies Pearls · CIBJO Pearl Book 2024
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- 'Keshi' is a trade term (from Japanese for 'poppy seed') not used on GIA reports; it should be qualified as 'keshi cultured pearl'.
- No growth duration or age.
- NBC and some natural pearl structures may overlap, so identification is not always conclusive (as the sources note).
- CIBJO Pearl Book 2024 (5.105/5.106) provides the naming definition and states that unqualified 'Keshi' is not recommended (5.105 note).
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
- Keshi Cultured Pearl
16 CFR Part 23 §23.21(e), §23.20(b), §23.19(a) · CIBJO Pearl Book 2024 §5.105
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Bleached (via parent material), Dyed (via parent material), Irradiated (via parent material)
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
Keshi Cultured Pearl is also known by several other names, some of which can refer to different materials in other contexts; use "Keshi Cultured Pearl" to avoid ambiguity.
Evidence
What this means for you
Before buying, check the recommended listing name "Keshi Cultured Pearl" 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
The normal and special care that applies to all natural and cultured pearls, and so to Keshi Cultured Pearl (CIBJO Pearl Book §7.1, §7.2; the source says this advice counts as normal across the whole range and should be passed on to the buyer), is set out in full under care on the Pearl entry.
Care
Keshi Cultured Pearl — care (light): may fade or revert to its original colour, so it should not be left for long periods in strong natural or artificial light or under strong display lighting.
CIBJO Pearl Book 2024
- Treatment state
- treated
- Only after these treatments
- dyeing
Source & check 2026-09-26
- Source
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §8.2 Annex C, Keshi Saltwater Cultured Pearl, p.53; §7.2, §7.2.2 (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
LightLight and display care for Keshi Cultured Pearl: as registered from the CIBJO Blue Book (Pearl Book, Pearl Commission 2024-1), for treated Keshi Cultured Pearl, and specifically for dyed Keshi Cultured Pearl, the colour may fade or revert to the original, so it should not be left for long periods under strong natural light, strong artificial light or strong display lighting. Special careThe CIBJO Blue Book (Pearl Book, Pearl Commission 2024-1) states that the general and special care advice common to natural and cultured pearls should be treated as standard for all kinds of pearls and passed on to the buyer; on that basis this site considers that it applies equally to Keshi Cultured Pearl, and the full advice is in the care part of the Pearl entry.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Light and display | may fade or revert to its original colour, so it should not be left for long periods in strong natural or artificial light or under strong display lighting |
Treatments and identification leads
One row per treatment, with three standards side by side: how often it occurs and how stable it is (CIBJO), its category in GB/T 16552—2017 Table B.1 (this site's paraphrase) and how the JJA/AGL 2025 table lists it. Each CIBJO value links to its entry under “Testing and market”, where the wording and source are given in full.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| Bleaching | — | — | Optimization | — | — |
| Dyeing | — | — | Treatment | — | — |
| Irradiation | — | — | Treatment | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Cultured Pearl)
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
VerifyNames, standards, technical facts, clauses and sources
Names
For Keshi Cultured Pearl, "Akoya Keshi cultured pearl", "Keshi Saltwater Cultured Pearl", "South-sea keshi cultured pearl" and "Tahitian keshi cultured pearl" are recorded with no restriction on use as a name, while "Keshi pearl" must not be used as a name (CIBJO Pearl Book 2024 §4.4.1.1.2; CIBJO Pearl Book 2024 §5.105).
Standard and listing namesThe name Keshi Cultured Pearl is not listed in the original Chinese standard, and the naming counterpart is cultured pearl (GB/T 16552—2017 Table A.3, row Cultured Pearl (Pearl)). The suggested listing name is Keshi cultured pearl (Keshi). Names in four languagesNames are given in Simplified Chinese, Traditional Chinese, English (Keshi Cultured Pearl) and Japanese; the wording of Japan's GSJ for the Japanese name is not yet verified by this site. Trade and mineralogical namesThe mineralogical name is a non-nucleated pearl formed as a by-product of cultured pearl operations. Sub-names and unacceptable namesCIBJO Pearl Book 2024 records the term Keshi and explicitly does not recommend the unqualified form Keshi; the name register lists Keshi pearl as a market name and an unusable name, kept only as a search term. Institution usageFor the English wording Keshi Cultured Pearl, the FTC text on file has no wording for this name (checked), and GIA, CIBJO and Gem-A are unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. National standard namesGermany (RAL) writes Keshi-Perle and the EU writes Keshi Pearl, noting that a cultured by-product must be disclosed.
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) | ||||
| Akoya Keshi cultured pearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Pearl Book 2024 §5.7 “Akoya Keshi cultured pearl” |
| Keshi Saltwater Cultured PearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Pearl Book 2024 Annex C §8.2 “Keshi Saltwater Cultured Pearl” |
| South-sea keshi cultured pearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Pearl Book 2024 §5.187 “South-sea keshi cultured pearl” |
| Tahitian keshi cultured pearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Pearl Book 2024 §5.196 “Tahitian keshi cultured pearl” |
| not to be used as a name (1) | ||||
| Keshi pearlEnglish | market name | matched automatically | not to be used as a name | CIBJO Pearl Book 2024 4.4.1.1.2; CIBJO Pearl Book 2024 §5.105; Note: CIBJO Pearl Book 2024 §5.105 marks unqualified “Keshi” as not recommended unless qualified as natural or cultured; kept for search only. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ケシ養殖真珠 (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)
- 养殖珍珠 (GB/T 16552—2017 Table A.3, row “Cultured Pearl(Pearl)”)
- Mineralogical name
- Non-nucleated pearl formed as a by-product of cultured pearl operations
- Trade names and synonyms
- Akoya Keshi cultured pearl (narrower name (variety or subtype)) · South-sea keshi cultured pearl (narrower name (variety or subtype)) · Tahitian keshi cultured pearl (narrower name (variety or subtype)) · Keshi Saltwater Cultured Pearl (narrower name (variety or subtype))Not to be used as a name: Keshi pearl (market name)
Four-language names
- 简体中文
- 客旭珍珠
- 繁體中文
- 客旭珍珠
- English
- Keshi Cultured Pearl
- 日本語
- ケシ養殖真珠
National and regional formal names
- Germany (RAL)
- Keshi-Perle
- European Union
- Keshi Pearl (EU: disclose if cultured by-product)
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural organic and biogenic materials
- Browsing family
- Pearl and molluscan shell materials
- Identity tier
- Organic or biogenic material
- Mineral chemical class
- Not applicable
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T 16552-2017, Annex B, Table B.1
Under the “Cultured Pearl (Pearl)” row of Table B.1: Bleaching Optimization; Dyeing Treatment; Irradiation Treatment. The full row, with the effect column, is on the Cultured Pearl page.
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
Among the material facts for Keshi Cultured Pearl, the structural, durability and optical items are all registered for cultured pearl (the whole class); they are not measurements of Keshi Cultured Pearl itself. Registered for cultured pearl (the whole class): the overall structure is an aggregate whose inorganic part is radially arranged, with aragonite orthorhombic and calcite trigonal, and whose organic part is amorphous; Mohs hardness 2.5–4; cleavage usually not seen in an aggregate; untreated, it effervesces on contact with acid. Also registered for cultured pearl (the whole class): optic character aggregate; refractive index 1.53–1.68, which the cited clause gives as a spot-method reading, a common value rather than an absolute limit, the clause having finer sub-ranges and the overall value being taken; birefringence not measurable for an aggregate; untreated, pleochroism not measurable for an aggregate; untreated, lustre pearly.
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”.
Luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for cultured pearl (the whole class), so they are not repeated on the Keshi Cultured Pearl page; see the material facts on the Cultured Pearl entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Keshi Cultured Pearl (how to read class-level values).
Definition
Keshi Cultured Pearl: a trade term that designates a non-beaded cultured pearl (5.139) formed accidentally or intentionally by human intervention in marine pearl oysters such as the Akoya oyster (Pinctada fucata 9.54), Silver/Gold lipped oyster (9.78) (Pinctada maxima 9.60), the Black lipped oyster (Pinctada margaritifera cumingii 9.58) and Pinctada radiata; it is a by-product of the culturing process. The creation results from the formation of a cultured pearl sac either following injury of the mantle rim upon human handling, from a partial piece of the inserted (grafted) mantle tissue (5.114) or the whole inserted piece (5.163) following the rejection of a bead (5.130). See also South-sea Keshi cultured pearl (5.187), Tahitian Keshi cultured pearl (5.196) and Akoya Keshi cultured pearl (5.7). Alternative name; Lagniappe (or Bonus) cultured pearl.
CIBJO Pearl Book 2024
- Qualification
CIBJO trade definition from an institutional manual, not a national standard. The English text quotes the full definition at §5.106 of the Pearl Book 2024.
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.106, p.32 (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Structure
Keshi Cultured Pearl — structure (overall): inorganic part: aragonite (orthorhombic) and calcite (trigonal) in radiating aggregates; organic part: amorphous.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Keshi Cultured Pearl — Mohs hardness: 2.5–4
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
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Keshi Cultured Pearl — cleavage: generally not seen on an aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Keshi Cultured Pearl — stability: effervesces in acid
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Keshi Cultured Pearl — feel (texture): feels gritty when two surfaces are rubbed together
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Keshi Cultured Pearl — optic character: aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Keshi Cultured Pearl — refractive index: 1.53–1.68
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
- Qualification
The clause we cite gives this as a value read by the spot (distant-vision) method. It is a common value, not an absolute limit.
- General note
- the clause has finer ranges
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Keshi Cultured Pearl — birefringence: not measurable on an aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Keshi Cultured Pearl — pleochroism: not measurable on an aggregate
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Quality factors
Keshi Cultured Pearl — quality factor (lustre): pearly
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- cultured pearl (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 (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.
Related CIBJO terms
- Akoya Keshi cultured pearl
a trade term for a keshi cultured pearl grown in Pinctada fucata (martensii) (9.54). An Akoya (5.5, 5.6) keshi cultured pearl (5.106) or an Akoya non-beaded cultured pearl formed accidentally in Pinctada fucata (martensii), it is a by-product of the culturing process. The creation results from the formation of a cultured pearl sac (5.54) either following injury of the mantle rim upon handling, or from a partial piece of the inserted (transplanted) mantle tissue (5.114), or the whole inserted piece (5.163) following the rejection of a bead (5.18).
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.7, p.22
- Keshi
an old Japanese trade name for a small saltwater natural or non-beaded cultured pearl that is essentially baroque in shape. Note: the term Keshi used without qualification has been misused and is not recommended terminology for any type of pearl product unless qualified with either ‘natural’ or ‘cultured’, whichever is appropriate.
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.105, p.32
- Lagniappe cultured pearls
cultured pearls that are a by-product of the freshwater culturing process in the USA, the term, is said to be derived from the New World Spanish la ñapa, "the gift," and ultimately from Quechua yapay, "to give more." The word came into the rich Creole dialect mixture of New Orleans and there acquired a French spelling. It is still used in the Gulf States of the USA, especially southern Louisiana, to denote a little bonus. By extension, it may mean "an extra or unexpected gift or benefit. See also Keshi cultured pearl (5.106).
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.107, p.33
- Non-nucleated cultured pearl
a term used in the trade for a non-beaded (5.139) and keshi (5.105) cultured pearls.
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.142, p.39
- South-sea keshi cultured pearl
a trade term for a keshi cultured pearl grown in Pinctada maxima (9.60). A South-sea (5.187) keshi cultured pearl (5.105) or a South-sea non-beaded cultured pearl formed accidentally in Pinctada maxima, it is a by-product of the culturing process. The creation results from the formation of a cultured pearl sac (5.54) either following injury of the mantle rim upon handling, or from a partial piece of the inserted (transplanted) mantle tissue (5.114), or the whole inserted piece (5.163) following the rejection of a bead (5.18). Some are hollow or contain relatively large amounts of organic matter.
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.187, p.44
- Tahitian keshi cultured pearl
a trade term for a keshi cultured pearl grown in Pinctada margaritifera cumingii in French Polynesia. The Tahiti keshi cultured pearl (see also 5.105) or Tahiti non-beaded cultured pearl (5.139), is formed accidentally in this pearl oyster in French Polynesia and is a by-product of the culturing process. The creation results from the formation of a cultured pearl sac (5.54) either following injury of the mantle rim upon handling, from a partial piece of the inserted (transplanted) mantle tissue (5.114) or the whole inserted piece (5.163) following the rejection of a bead (5.18). Some Tahiti keshi cultured pearls are hollow or contain relatively large amounts of organic matter.
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.196, p.45
- Tissue nucleated cultured pearl
a term used in the trade for a non-beaded cultured pearl.
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.203, p.46
Entries in the source that only point to another clause: Bonus cultured pearl (§5.30, p.25) → §5.106 Keshi cultured pearl
Definitions are quoted verbatim from the cited CIBJO Blue Book; […] marks an excerpt, and the full definition is at the cited clause.
Pearl-producing molluscs (CIBJO Annex D): §9.54 Pinctada fucata · §9.58 Pinctada margaritifera cumingii · §9.60 Pinctada maxima · §9.78 Silver-lipped pearl oyster
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.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia.
- Gem-A – The Gemmological Association of Great Britain (United Kingdom).
- eCFR (United States). 16 CFR § 23.21 — Misuse of terms such as “cultured pearl,” “seed pearl,” “Oriental pearl,” “natura,” “kultured,” “real,” “synthetic,” and regional designations. In: 16 CFR Part 23 — Guides for the Jewelry, Precious Metals, and Pewter Industries.
Further reading
Related entries and topic cluster
Parent entry and related pages on this site. Rows marked “Planned” are suggested new content and have no link yet.
Related-entry tree for Pearl on this site: 17 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Keshi Cultured Pearl) is marked.
- Pearl
Sub-entries (16)
- Abalone Pearl
- Akoya Cultured Pearl
- Baroque Cultured Pearl
- Blister Pearl
- Circled Cultured Pearl
- Cultured Pearl
- Freshwater Cultured Pearl
- Freshwater Natural Pearl
- Keshi Cultured Pearl
- Natural Conch Pearl / Natural Melo Pearl
- Natural Pearl
- Saltwater Cultured Pearl
- Saltwater Natural Pearl
- South Sea Cultured Pearl
- Tahitian Cultured Pearl
- White South Sea Cultured Pearl
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Pearl and molluscan shell materials | Live |
| Treatments recorded for this material | Bleached (via parent material), Dyed (via parent material), Irradiated (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Keshi Cultured Pearl entry are maintained by the LumaLark wiki and matched one by one to the standard clauses or institutional sources they cite: every fact carries its source (with a clause or page locator) and a check date, so it can be traced back to the original. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.