On this page
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
Blister Pearl
Also known asCultured Blister Pearl · Natural Blister Pearl
A pearl attached to the inner wall of a shell. A natural one forms when a pearl breaks through the mantle and attaches to the inner shell; a cultured one grows from a nucleus implanted against the inner shell, its flat side joined to the shell (GB/T 18781 calls it an attached-shell pearl).
It differs from mabe, an assembled product cut off, filled and backed with mother-of-pearl. 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 Blister Pearl forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify Blister PearlIdentification points from the research literature
- Caring for and wearing Blister PearlCleaning, heat, chemicals and light, as the cited sources give them
- Blister Pearl in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Has any of GIA, FTC, CIBJO or Gem-A put a name for it on record here?
- Listing and disclosing Blister 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
A blister pearl is a natural or cultured pearl that grows attached to the inner wall of a mollusk shell; culturists grow them by cementing a nucleus (often resin) onto the inner shell wall near the adductor muscle, so they are also called cultured half-pearls or mabe (mabe or cultured blister pearls). Its formation involves the mantle epithelium: after implantation, the mantle epithelium secretes nacre over the nucleus, and the nacre covers the nucleus layer by layer while remaining joined to the shell wall, producing a hemispherical pearl that is half raised and half attached. Blister pearls are related to, but not identical with, mabe pearls: the source uses “mabe” for cultured half-pearls (blisters), whereas cutting, filling, and backing a half-pearl to make an assembled product is later processing outside this source's account of formation.
Scope: Used to explain the attached formation of blister pearls on the inner wall of the shell; no assertion is made about the processing details of assembled mabe products made by cutting and filling.
Sources CIBJO Pearl Book 2024 · G&G Fall 2019
Where it forms
The inner wall of the mollusk shell near the adductor muscle, where the nacre sac joins the shell
Sources G&G Fall 2019
A marine farm (e.g., Pteria penguin), with mollusks suspended about 2 m below the surface
Sources G&G Fall 2019
How it forms, step by step
A ~17 mm resin nucleus is cemented to the inner shell wall near the adductor muscle with an ethyl-2-cyanoacrylate glue.
The mantle epithelium secretes nacre over the nucleus, forming a nacre sac.
Nacre is deposited and thickens layer by layer (~1.2 mm nacre; nucleus plus pearl layer ~19.4 mm).
At harvest the pearl is still attached to the shell wall and is hemispherical.
Distinguished from the later cutting/filling/backing of an assembled mabe product.
Link to appearance
Hemispherical with one face attached to the shell; nacre thickness and colour vary with the mollusk and growing conditions.
Sources CIBJO Pearl Book 2024 · G&G Fall 2019
Timescale
The half-pearl trial lasted roughly ten months. At harvest, about the seventh month in, nucleus and pearl layer together measured as much as about 19.4 mm across, with a nacre coat of about 1.2 mm — the thickness considered best for buttons and button-shaped jewellery.
Sources G&G Fall 2019
Related base materials
- Pearl: A blister pearl is a pearl form grown attached to the inner wall of the shell; the material is still nacre/pearl
Supporting findings
A blister pearl is a natural or cultured pearl formed attached to the inner wall of a mollusk shell; mollusks such as Pteria penguin are commonly used to produce half-pearls (mabe or cultured blister pearls).
Evidence grade AScope: Describes attachment-style formation on the shell wall; does not cover assembling a mabe product.
Cultured half-pearls are grown by cementing a resin nucleus onto the inner shell wall near the adductor muscle, after which the mantle epithelium secretes nacre layer by layer over the nucleus.
Evidence grade AScope: The standard half-pearl culture process; not every species/operational variant.
Half-pearls are grown for about 10 months, and harvesting around the seventh month gives a nucleus plus pearl layer of ~19.4 mm and nacre ~1.2 mm thick, the optimum for buttons and button-shaped jewelry.
Evidence grade AScope: An experimental result for Pteria penguin half-pearls, not a universal rule for all blister pearls.
Recorded localities
This is an organic material; its localities are the harvest or culture areas (waters or species ranges) recorded by authoritative sources.
Asia
- Phuket, ThailandPteria penguin cultured half-pearls
Sources Gems & Gemology Fall 2019
Oceania
- Halfmoon Bay, Stewart Island, New ZealandCultured abalone (Haliotis iris) blister pearls
Sources Gems & Gemology Fall 1998
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
Cultured, natural and imitation pearls can look alike, so the unaided eye cannot fix their category or whether a pearl was treated. Laboratory identification combines standard gemmological testing with advanced equipment: real-time X-ray radiography and microradiography gauge nacre-layer depth in bead-cultured pearls, UV-Vis reflectance spectroscopy and X-ray fluorescence (XRF) help determine pearl type and detectable treatments, and computed micro-tomography (micro-CT) may be used when finer data are needed. Limitations: classification depends on comparison with reference master sets, thin nacre makes instrumental measurement still more necessary, and the final conclusion must be issued by an accredited pearl laboratory through testing.
Evidence grade AScope: Identification and classification points; testing must be performed by an accredited pearl laboratory, and no self-test thresholds are given.
Sources GIA: How GIA Identifies Pearls · CIBJO Pearl Book 2024
Other research findings
Blister pearls and mabe pearls are related but not identical: the source calls cultured half-pearls (blisters) “mabe,” while cutting, filling, and mother-of-pearl backing of a half-pearl is later processing outside this source's account of formation.
Evidence grade BScope: The mechanistic link is supported by the source; the assembled-product part relies on domain knowledge rather than this source, hence rated B.
CIBJO separates cultured blister pearls (clause 5.53) from natural ones (clause 5.134). In both cases the pearl has pushed through the mantle (in freshwater) or the gonad cavity and, by means of nacreous or non-nacreous material the mollusc lays down, it has become fixed to the shell's inner wall; the layers added afterwards run on continuously with those of that wall.
Evidence grade AScope: The naming/formation clauses (5.53 and 5.134); defines blister pearls by perforation of the mantle/gonad and adhesion to the inner shell wall.
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). A blister pearl grows attached to the inner surface of the shell, and its evaluation must state that blister nature: emphasis falls on the lustre, shape and colour of the shell-facing surface and on a form and use that differ from a whole free pearl; because it grows against the shell, its back or base differs from that of a free round pearl and the evaluation criteria shift accordingly. 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
- CIBJO Pearl Book 2024 clauses 5.53 and 5.134 now directly define the names cultured/natural blister pearl; the original GIA source describes rearing of cultured half-pearls.
- Processing details of the assembled mabe product (cutting/filling/backing) are outside this source, so that distinction is rated B.
- The specific formation of natural blister pearls is defined by clause 5.134 as the pearl sac perforating the mantle and naturally adhering to the inner shell wall.
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
- Blister pearl (state natural or cultured)
GB/T 16553—2017 §5.3.2.3 · GB/T 18781—2023 3.2
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
"Blister Pearl" is a market name rather than a mineral species name; before using it, verify: An explicit qualifier must accompany the name.
Evidence
- GB/T · §5.3.2.3
What this means for you
Before buying, check the recommended listing name "Blister pearl (state natural or cultured)" 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
- 2026-09-26
Trade-name ruling
- An explicit qualifier must accompany the name.
- Suggested listing name
- Blister pearl (state natural or cultured)
Care and wear
Care
Blister Pearl — care (wear): Abalone (9.1) as well as natural and cultured blisters (5.133 and (5.57) are prone to fracture easily and shall have special care advice that includes instructions that they are not for everyday wear and should not be worn while carrying out heavy work.
CIBJO Pearl Book 2024
- Treatment state
- any treatment state
- Applies only to
- abalone pearls, natural blisters and some cultured blisters
Source & check 2026-09-26
- Source
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §7.2.1 (Annex B, normative), p.49 (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
On care and wear of Blister Pearl, the Pearl Book 2024 of CIBJO, the World Jewellery Confederation, states that Blister Pearl breaks easily, so it is not meant for everyday wear and should not be worn during heavy work. This applies to any treatment state, and the scope covers only abalone pearls, natural blister pearls and some cultured blister pearls.
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| Question | Matching entries |
|---|---|
| Wearing limits (knocks, settings) | abalone pearls, natural blisters and some cultured blisters: care (wear) |
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Blister Pearl, the name register records "Cultured Blister Pearl" and "Natural Blister Pearl", 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).
Names in four languagesFour-language names for Blister Pearl are given in Simplified Chinese, Traditional Chinese, English (Blister Pearl) and Japanese (pending verification). Trade and mineralogical namesTrade names/synonyms include Natural Blister Pearl, Cultured Blister Pearl and a Chinese term for blister-type pearl. The mineralogical name describes a natural or cultured pearl attached to the inner wall of a mollusc shell. Standard and listing namesThe suggested listing name is Blister Pearl (state natural/cultured). Under the GB/T 16552—2017 Table A.3 naming counterpart, the basic name must be determined by testing, and Blister Pearl is not listed in the original. Institution usageOn authority wording, 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. Japanese namesThe formal name of Japan's GSJ is shown as the Japanese form marked pending verification; the wording of Japan's GSJ for this name is not yet verified by this site, and the entry's own Japanese name is shown.
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 (3) | ||||
| Cultured Blister PearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| Natural Blister PearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| 附壳型珍珠Simplified Chinese | narrower name (variety or subtype) | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ブリスター・パール（待核） (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)
- basic name to be determined by testing (GB/T 16552—2017 Table A.3)
- Mineralogical name
- Blister pearl: a natural or cultured pearl adhered to the inner wall of the mollusc shell
- Trade names and synonyms
- Natural Blister Pearl (narrower name (variety or subtype)) · Cultured Blister Pearl (narrower name (variety or subtype))
Four-language names
- 简体中文
- 附壳珍珠
- 繁體中文
- 附殼珍珠
- English
- Blister Pearl
- 日本語
- ブリスター・パール（待核）
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
What it is and how it's identified
Among the registered material facts for Blister Pearl, magnification shows growth striations on one surface and a layered structure on the other. The treatment state for magnification is untreated, and the source is GB/T 16553—2017 Gems — Testing. This site's qualifying note points out that the cited GB/T clause gives magnification within the cultured pearl section, so it refers to cultured blister pearl.
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”.
Optical
Blister Pearl — magnification: One side shows surface growth striations; the other side shows a layered structure.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives this under cultured pearls, so it describes cultured blister pearls.
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.
Pearl-producing molluscs (CIBJO Annex D)
Pearl-producing molluscs (CIBJO Annex D): §9.1 Abalone
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.
- CIBJO – The World Jewellery Confederation. The Pearl Book (Blue Book), 2024.
- AQSIQ / SAC (China). GB/T 16553—2017 Gems — Testing.
- SAMR / SAC (China). GB/T 18781—2023 Cultured pearl grading.
- SAMR / SAC (China). GB/T 16552—2017 Gems — Nomenclature.
- eCFR (United States). 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 (Blister 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 |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Blister 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.