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Natural organic and biogenic materials · Shape / bead-form / specification term · Cultured formation; treatments recorded separately

Circled Cultured Pearl

Also known ascircle pearl (not to be used as a name) · circled pearl (not to be used as a name) · ringed pearl (not to be used as a name)

A cultured pearl with one or more concentric rings or grooves on its surface; the rings must be confirmed as growth features, and the name describes shape only. 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.

Edited by RalphReviewed by JuneLast updated 2026-10-12Who maintains this page

Care and wear

What this page can answer

This page covers

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

Ringed (circled) cultured pearl refers to a cultured pearl bearing one or more concentric surface rings or grooves; it is a descriptive trade term based on surface/shape character rather than an independent pearl material. The appearance is linked to the layered growth of nacre: the mantle epithelium forms a nacre sac around the implant and secretes nacre layer by layer inward and onto the bead, and the nacre accumulates as concentric growth layers that can appear at the pearl surface as rings or grooves. Authoritative gemological sources discuss nacre's layered deposition and the internal concentric growth structures of pearls but do not define the specific trade name “ringed/circled cultured pearl,” so its exact classification requires case-by-case testing.

Scope: Used to explain the relationship between the surface ring features of circled cultured pearls and the layered growth of nacre; no authoritative definition is given for this commercial name.

Sources CIBJO Pearl Book 2024 · G&G Fall 2021 · GIA Pearl Description (Chinese edition) +1

Where it forms

The nacre sac formed by mantle epithelium inside the mollusk

Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

Marine or freshwater farm waters; the secretory interface where nacre is deposited layer by layer

Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

How it forms, step by step

  1. A bead nucleus and mantle tissue (or only mantle tissue) are implanted into the mollusk.

    Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

  2. The mantle epithelium forms a nacre sac around the implant and secretes nacre.

    Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

  3. Nacre accumulates layer by layer as concentric growth layers.

    Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

  4. Undulation or interruption of the growth layers appears at the pearl surface as one or more rings or grooves.

    Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

  5. The exact classification of this trade name requires testing the sample.

    Sources G&G Fall 2021 · GIA Pearl Description (Chinese edition)

Link to appearance

One or more concentric surface rings or grooves, related to the way nacre deposits as concentric growth layers.

Sources CIBJO Pearl Book 2024 · G&G Fall 2021 · GIA Pearl Description (Chinese edition) +1

Timescale

No source gives a time for the formation of the ring/groove surface feature; sources only state that Pinctada maxima cultured pearls generally require a minimum growth period of about two years.

Sources CIBJO Pearl Book 2024 · G&G Fall 2021 · GIA Pearl Description (Chinese edition) +1

Related base materials

  • Cultured pearl: Description of cultured pearls by surface/shape features, not an independent material

Supporting findings

Nacre is secreted layer by layer by the mantle nacre sac and accumulates inside the pearl as concentric growth layers (concentric rings); the surface rings represent such growth layers.

Evidence grade B

Scope: Linking internal concentric growth layers to surface rings is an interpretive inference, hence rated B.

Sources G&G Fall 2021

Cultured pearls form when the mantle epithelium builds a nacre sac around the implant and secretes nacre inward and onto the bead layer by layer.

Evidence grade A

Scope: The generic formation of cultured pearls, not unique to ringed pearls.

Sources GIA Pearl Description (Chinese edition)

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 A

Scope: 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

The CIBJO Pearl Book 2024 defines 'Circled' (5.40) - cerclé in the older numbering (5.35) - as a pearl bearing concentric rings or indented grooves, one or more of them, on its surface; 'ringed/circled cultured pearl' is a descriptive trade name resting on this shape/surface feature, and each case must be verified by testing.

Evidence grade A

Scope: Naming definition from CIBJO 5.40/5.35; the standard defines the description 'a pearl with concentric rings or grooves', not an identification result for an individual sample.

Sources GIA: How GIA Identifies Pearls · CIBJO Pearl Book 2024

Size and shape are routine pearl-grading dimensions; shape/surface are included among the pearl value factors, showing that surface/shape-based naming is a grading convention.

Evidence grade A

Scope: A statement of grading dimensions, not a definition of the “ringed” name.

Sources GIA: How GIA Identifies Pearls

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). Ringed cultured pearls carry concentric rings or grooves on their surface, which is their signature surface feature; evaluation emphasises the strength of lustre, the condition of the rest of the surface, colour, and the regularity and evenness of the rings themselves, rather than applying a 'flawless and round' standard. The rings are a surface feature, and how they are judged aesthetically varies with design. Category and any treatment must be determined by an accredited laboratory through testing.

Evidence grade A

Scope: 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
  • 'Ringed/circled cultured pearl' is a descriptive trade name; CIBJO 5.40 (circled/cerclé) defines 'a pearl with concentric rings or grooves' but does not use the Chinese trade name.
  • The sources discuss internal concentric growth layers, not directly the surface ring/groove feature.
  • No timescale is given for the formation of the surface feature.

Methodology

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
Circled Cultured Pearl (state freshwater or saltwater)

GB/T 18781—2023 Table 1, 3.15 · CIBJO Pearl Book 2024 §5.40

Construction or treatment status

Cultured formation; treatments recorded separately

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

"Circled Cultured 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 · Table 1, section 形状级别 (Shape Grade)

What this means for you

Before buying, check the recommended listing name "Circled Cultured Pearl (state freshwater or saltwater)" 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

Trade-name ruling

  • An explicit qualifier must accompany the name.
Suggested listing name
Circled Cultured Pearl (state freshwater or saltwater)

Care and wear

The normal and special care that applies to all natural and cultured pearls, and so to Circled 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

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

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.

TreatmentMarket frequency (CIBJO)Stability (CIBJO)GB/T 16552 categoryJJA/AGL listingIdentification 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 Circled Cultured Pearl, "circle pearl", "circled pearl", "circlé pearl" and "ringed pearl" must not be used as a name (CIBJO Pearl Book 2024 §5.40; CIBJO Pearl Book 2024 §4.4.1.1.2; CIBJO Pearl Book 2024 §5.35 “Cerclé or circled see circled 5.40.”); 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).

Standard and listing namesThe suggested listing name for Circled Cultured Pearl is Circled Cultured Pearl (stating freshwater or saltwater). The name is not listed in the standard; its GB/T naming counterpart is cultured pearl (the cultured pearl row of GB/T 16552—2017 Table A.3). Trade and mineralogical namesTrade names or synonyms include a Chinese market name meaning “threaded pearl” and circled pearl, while low-confidence search variants are ringed pearl, circle pearl and circlé pearl. Names in four languagesNames are registered in four languages: Simplified Chinese, Traditional Chinese, English (Circled Cultured Pearl) and Japanese; the Japanese form is the entry's own, and the wording used by the GSJ (Japan) for the Japanese name is not yet verified by this site. Institution usageOn authority wording, the FTC and CIBJO texts on file have no wording for Circled Cultured Pearl (checked), and GIA and Gem-A are unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. Trade and mineralogical namesAmong the registered names, the “threaded pearl” name is a market name; circled pearl is linked to the high-risk name “Pearl” and must not be used as a name. Candidate search termsCircle pearl, circlé pearl and ringed pearl are used only as candidate search terms.

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.

NameTypeMatchingUse as a nameBasis
no restriction recorded (1)
螺纹珍珠Simplified Chinesemarket namematched automaticallyno restriction recordedCIBJO Pearl Book 2024 §5.40; CIBJO Pearl Book 2024 §5.35 “Cerclé or circled see circled 5.40.”; GB/T 18781—2023 Table 1; GB/T 18781—2023 3.15; 16 CFR Part 23 §23.19(a)
not to be used as a name (4)
circle pearlEnglishmarket namesearch candidate onlynot to be used as a nameCIBJO Pearl Book 2024 §5.40; CIBJO Pearl Book 2024 4.4.1.1.2
circled pearlEnglishmarket namematched automaticallynot to be used as a nameCIBJO Pearl Book 2024 §5.40; CIBJO Pearl Book 2024 4.4.1.1.2; Note: Related high-risk name “Pearl”.
circlé pearlEnglishmarket namesearch candidate onlynot to be used as a nameCIBJO Pearl Book 2024 §5.35 “Cerclé or circled see circled 5.40.”; CIBJO Pearl Book 2024 §5.40; CIBJO Pearl Book 2024 4.4.1.1.2
ringed pearlEnglishmarket namesearch candidate onlynot to be used as a nameCIBJO Pearl Book 2024 §5.40; CIBJO Pearl Book 2024 4.4.1.1.2

How each authority words this name: see Names › Authority wording.

Authority wording

GIA, FTC, CIBJO, Gem-A
Circled Cultured Pearl (no wording for this name in the FTC, CIBJO text on file; GIA, Gem-A unchecked — bodies without a recorded wording show the entry's own English name)
GSJ (Japan) formal name
サークル養殖真珠 (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
Cultured pearl with one or more concentric rings or grooves
Trade names and synonyms
Not to be used as a name: circled pearl (market name) · ringed pearl (market name) · circle pearl (market name)

Four-language names

简体中文
环纹养殖珍珠（螺纹珍珠）
繁體中文
環紋養殖珍珠（螺紋珍珠）
English
Circled Cultured Pearl
日本語
サークル養殖真珠

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
Shape / bead-form / specification term
Mineral chemical class
Not applicable
Construction or treatment status
Cultured formation; treatments recorded separately

Treatments listed by standards

Circled Cultured Pearl is classified by applying the “Cultured Pearl (Pearl)” row of GB/T 16552—2017, Annex B, Table B.1: bleaching is listed as an optimization, and dyeing and irradiation as treatments. Applying the “Cultured Pearl (Pearl)” row is this site's practice; GB/T 16552—2017 Table B.1 itself does not list Circled Cultured Pearl separately. What Table B.1 is and how the grades it refers to are defined are on the Gem treatments page.

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

The registered material facts for Circled Cultured Pearl all take the cited clause's values for cultured pearl (the whole class), not measurements of Circled Cultured Pearl itself. Registered for cultured pearl (the whole class): structure overall is an aggregate whose inorganic part is radially arranged, with aragonite orthorhombic and calcite trigonal, and the organic part amorphous; Mohs hardness 2.5–4; cleavage usually not seen in the aggregate; stability, untreated: effervesces on contact with acid; feel: the surface feels gritty when rubbed. Optically, for cultured pearl (the whole class), optic character is aggregate; refractive index 1.53–1.68, with site notes that this is a spot-method reading, a typical value rather than an absolute limit, and that the clause also gives finer sub-ranges, with the overall value used; birefringence not measurable on an aggregate; pleochroism, untreated, not measurable on an aggregate; quality factor (lustre), untreated, 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 Circled 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 Circled Cultured Pearl (how to read class-level values).

Structure

Circled 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

Circled Cultured Pearl — Mohs hardness: 2.5–4

GB/T 16553—2017

123456789102.5–4References (diamond = value, bar = range; below)

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))

Mohs hardnessSource: 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

Circled 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

Circled 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

Circled 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

Circled 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

Circled Cultured Pearl — refractive index: 1.53–1.68

GB/T 16553—2017

1.31.72.12.52.93.31.53–1.68
Refractive indexSource: 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

Circled 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

Circled 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

Circled 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

Circled

a pearl also known as cerclé (5.35) with one or more concentric rings or indented grooves around it.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.40, p.26

Entries in the source that only point to another clause: Cerclé or circled (§5.35, p.25) → §5.40 Circled

Definitions are quoted verbatim from the cited CIBJO Blue Book; […] marks an excerpt, and the full definition is at the cited clause.

Evidence and sources

Authority basis and clause sources

GB/T 18781—2023
Naming rule Table 1 · Source
GB/T 18781—2023
Naming rule 3.15 · Source
CIBJO Pearl Book 2024
Listed §5.40 · Source

Sources

Further reading

Related pages

Treatments recorded for this material

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 (Circled Cultured Pearl) is marked.

This table scrolls sideways on narrow screens.

PageContentStatus
Browsing familyPearl and molluscan shell materialsLive
Treatments recorded for this materialBleached (via parent material), Dyed (via parent material), Irradiated (via parent material)Live
Related articlesTo be added (placeholder)Planned

Who maintains this page

The material facts in the Circled 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.

Facts editor
Ralph
Reviewer
June
How facts are checked
Each fact is matched to the clause it cites; facts checked on 2026-09-26
Last revised
2026-10-12
Purpose
Lets buyers and sellers check naming, disclosure and material facts clause by clause.

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