On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural organic and biogenic materials · Organic or biogenic material · Cultured formation; treatments recorded separately
Freshwater Cultured Pearl
Also known asBiwa cultured pearl (annotation only, never as the product name) · Freshwater Pearl (conditional name) · Soufflé freshwater cultured pearl
A cultured pearl formed with human intervention inside a freshwater mollusc; under GB/T 16552-2017 it may be shortened to "freshwater pearl". Also known as Freshwater 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 Freshwater Cultured Pearl forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify Freshwater Cultured PearlIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Freshwater Cultured PearlThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Freshwater Cultured PearlCleaning, heat, chemicals and light, as the cited sources give them
- Hardness and refractive index of Freshwater Cultured PearlEach value with its source and check date
- Freshwater Cultured 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 Freshwater 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
One way they may be produced, the non-beaded (tissue-only) method, step by step:
- Several pieces of mantle tissue without a bead are implanted into the host mollusk's mantle.
- Nacre forms around each implanted tissue piece and is deposited layer by layer.
Freshwater cultured pearls are cultured pearls formed in freshwater mollusks with human intervention. The common path is tissue-only (non-beaded) nucleation: several pieces of mantle tissue without a bead are implanted into the host's mantle, and nacre forms around each implanted piece, so many pearls are often raised in a single mussel. They are generally grown in lakes and ponds of freshwater, are comparatively inexpensive, and come in a wide range of sizes, shapes and colours. American freshwater pearls come from the Unio mussel, and the freshwater cultured pearl is a newer addition to that industry.
Scope: Covers the tissue-nucleated (non-beaded) origin of freshwater cultured pearls and their freshwater mussel hosts; distinguished from the bead-nucleation pathway of saltwater cultured pearls.
Sources GIA Pearl Description · GIA Pearl Description (Chinese edition) · CIBJO Pearl Book 2024 +1
Where it forms
Freshwater lakes and ponds: the main culturing waters, where many pearls are often grown in one oyster.
Sources GIA Pearl Description · G&G Fall 1984
Inside freshwater mussels such as the Unio: the host of North American freshwater pearls.
Sources GIA Pearl Description · G&G Fall 1984
How it forms, step by step
Several pieces of mantle tissue without a bead are implanted into the host mollusk's mantle.
Sources GIA Pearl Description (Chinese edition)
Nacre forms around each implanted tissue piece and is deposited layer by layer.
Sources GIA Pearl Description (Chinese edition)
Several pearls grow concurrently in one host and are harvested as freshwater cultured pearls.
Sources GIA Pearl Description
Link to appearance
The tissue-only path gives freshwater cultured pearls a wide range of shapes, sizes and colors, often including irregular (baroque) forms; the nacre is controlled by deposition around the implanted tissue.
Sources GIA Pearl Description
Timescale
The sources give no growth duration and no absolute age for freshwater cultured pearls; they state only that these pearls are generally grown in lakes and ponds of freshwater.
Sources GIA Pearl Description
Related base materials
- Freshwater mollusk (e.g. Unio mussel): biogenic-host | Freshwater cultured pearls form inside freshwater mussels; the host is the biogenic parent
Supporting findings
Freshwater cultured pearls are generally grown in lakes and ponds of freshwater, and often many pearls are raised within a single oyster.
Evidence grade AScope: Authoritative description of the culturing environment, noting multiple pearls per host.
Sources GIA Pearl Description · GIA Pearl Description (Chinese edition)
Freshwater cultured pearls may be produced by a non-beaded (tissue-only) method: mantle tissue pieces without a nucleus are implanted into the host's mantle, and nacre forms around each implanted piece.
Evidence grade AScope: Describes the tissue-only path commonly used for freshwater pearls; does not exclude other paths.
Sources GIA Pearl Description (Chinese edition)
Recorded localities
This is an organic material; its localities are the harvest or culture areas (waters or species ranges) recorded by authoritative sources.
Asia
- ChinaFreshwater; Hyriopsis cumingii is now the main pearl mussel used in China
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- Taiwan, ChinaFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- VietnamFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- Lake Biwa, Shiga, JapanFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- Lake Kasumigaura, Ibaraki, JapanFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- ThailandFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- IndiaFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- PhilippinesFreshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
- Korea (as printed)Freshwater
Sources CIBJO Pearl Book 2024
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1)
North America
- United StatesFreshwater; cultured blister pearls
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 how far testing can go on this page, the origin determination guide and the overview of recorded localities.
How it is identified
A freshwater cultured pearl can mimic a saltwater cultured or natural pearl in shape, and the eye cannot tell them apart. The judgement must be made in a laboratory: routine gemological tests together with X-ray fluorescence, real-time X-radiography and UV-Vis reflectance spectroscopy, plus nacre-thickness measurement when needed, are required; the result should come from an accredited laboratory.
Evidence grade AScope: Determining freshwater culture origin requires professional laboratory testing; this entry is not a do-it-yourself identification basis.
Sources GIA: How GIA Identifies Pearls
Other research findings
The host of American freshwater pearls is the Unio mussel, and the freshwater cultured pearl is a newer entry to the American pearl industry.
Evidence grade BScope: From the 1984 GIA article abstract, reflecting the North American pearl industry context of that time.
Sources G&G Fall 1984
Because of their wide range of sizes, shapes and colors and their comparatively low price, freshwater cultured pearls are among the most commonly produced pearl types.
Evidence grade BScope: A market-characteristic description rather than a formation mechanism; used to note the material's prevalence.
Sources GIA Pearl Description
CIBJO's definition of freshwater cultured pearls covers cultured pearls grown in freshwater molluscs, mussels, such as Hyriopsis schlegeliii, Hyriopsis cumingii and Megalonaias nervosa.
Evidence grade AScope: The naming definition (clause 5.77); defines freshwater cultured pearls by freshwater environment and mussel hosts.
Sources CIBJO Pearl Book 2024
Freshwater cultured pearls are assessed by lustre, surface, shape, colour and matching. Most are tissue-nucleated and contain no bead, so the 'nacre thickness' measure used for bead-cultured pearls does not apply; assessment emphasises lustre, surface cleanliness, shape and the consistency of matching across a strand. Compared with saltwater cultured pearls the emphasis differs: bead-cultured saltwater pearls weigh nacre thickness, while freshwater pearls weigh lustre and surface more. Imitation pearls are not subject to pearl quality assessment.
Evidence grade AScope: Quality factors describe which characteristics the market generally prizes; they are not a grade for any specific specimen and are neither price nor investment advice. Pearl quality assessment must be issued by an accredited laboratory for a specific specimen.
Sources CIBJO Pearl Book 2024 · GIA: How GIA Identifies Pearls
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- Sources give no growth duration or absolute age for freshwater cultured pearls.
- The 1984 source is only an abstract with limited detail; specific Chinese freshwater locality data is not included.
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
- Freshwater Cultured Pearl
GB/T 16552—2017 Table A.3 “Freshwater Cultured Pearl”, 5.1.2.3 b)
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
"Freshwater Cultured Pearl" is a market name rather than a mineral species name; before using it, verify: Laboratory identification required before the name is used.
What this means for you
Before buying, check the recommended listing name "Freshwater Cultured Pearl" 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
- Laboratory identification required before the name is used.
- Suggested listing name
- Freshwater Cultured Pearl
Care and wear
The normal and special care that applies to all natural and cultured pearls, and so to Freshwater 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
Freshwater 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, Freshwater Cultured Pearl, p.53; §7.2, §7.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Freshwater Cultured Pearl — care (special care): freshwater cultured pearls dyed any colour: special care (SC); keep away from cosmetics.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- treated
- Only after these treatments
- dyeing
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XIII, Gemstone Information Chart, Pearl Cultured D (freshwater), CARE REQUIRED / SPECIAL ADVICE (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-related care for Freshwater Cultured Pearl applies only to dyeing, with the treatment state treated: dyed Freshwater Cultured Pearl 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). AGTAThe AGTA Gemstone Information Manual, 17th edition, records that Freshwater Cultured Pearl dyed in various colours needs special care (marked SC) and should be kept away from cosmetics; this special care likewise applies only to dyeing, with the treatment state treated. Special careGeneral and special care that apply to all natural and cultured pearls, and so also to Freshwater Cultured Pearl, are listed in full in the care part of the Pearl entry; the original CIBJO Pearl Book 2024 says that this care advice should be regarded as routine for all kinds of pearl and should be passed on to the buyer.
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
What this table covers
What this page can give
- Registered treatments, their stability and how often they occur (see the table above)
- Identification leads for each treatment, for use when sending a stone for testing
VerifyNames, standards, technical facts, clauses and sources
Names
For Freshwater Cultured Pearl, "Freshwater Pearl", "Freshwater cultured pearl" and "Soufflé freshwater cultured pearl" are recorded with no restriction on use as a name, while "Biwa cultured pearl" may appear only as an annotation, never as the product name (CIBJO Pearl Book 2024 §5.22 “Biwa cultured pearl”; GB/T 16552—2017 §5.1.2.3 c); GB/T 16552—2017 §5.1.1 c)); 7 further names in non-Latin scripts are listed in the name register below (7 with no restriction recorded on use as a name).
Standard and listing namesThe Chinese formal name of Freshwater Cultured Pearl comes from the “Freshwater cultured pearl (freshwater pearl)” entry in GB/T 16552—2017 Table A.3; the suggested listing name is likewise Freshwater Cultured Pearl, with freshwater pearl recorded as the short form. Trade and mineralogical namesMarket names include Freshwater cultured pearl and the Chinese name for aurora freshwater pearl, recorded on the basis of an editorial ruling by this site (no clause cited); aurora is a quality designation from a testing laboratory, not a material type. Names in four languagesThe four-language names are the Simplified and Traditional Chinese names, English Freshwater Cultured Pearl and the Japanese name; the Japanese form is the entry's own, and GSJ's wording for this name is not yet verified by this site. Institution usageFor authority wording, FTC has been checked and its text on file has no wording for Freshwater Cultured Pearl; GIA, CIBJO and Gem-A wording is unchecked, and the English name shown for bodies without a recorded wording comes from the entry itself and does not represent their position. Candidate search termsFreshwater Pearl is a search candidate only, as its basis includes a draft for comment not in force and it runs counter to international pearl nomenclature; Biwa cultured pearl may only be added as a note and must not be the main product name.
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 (10) | ||||
| Freshwater PearlEnglish | short form | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 5.1.2.3 b); CIBJO Pearl Book 2024 Annex C §8.1 “Freshwater Pearl”; Note: Draft standard for comment, not in force; the usage is the opposite of international pearl nomenclature. |
| Freshwater cultured pearlEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| Soufflé freshwater cultured pearlEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Pearl Book 2024 §5.184 “Soufflé freshwater cultured pearl” |
| 三角帆蚌淡水珍珠Simplified Chinese | narrower name (variety or subtype) | matched automatically | no restriction recorded | GB/T 18781—2023 3.2.2 |
| 康乐蚌淡水珍珠Simplified Chinese | narrower name (variety or subtype) | matched automatically | no restriction recorded | GB/T 18781—2023 3.2.2 |
| 极光淡水珍珠Simplified Chinese | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Related high-risk name “Australian white, Tennyo, Aurora, Baroque”: “Aurora” is a laboratory quality designation, not a material. |
| 池蝶蚌淡水珍珠Simplified Chinese | narrower name (variety or subtype) | matched automatically | no restriction recorded | GB/T 18781—2023 3.2.2 |
| 淡水珍珠Simplified Chinese | short form | matched automatically | no restriction recorded | GB/T 16552—2017 5.1.2.3 b); GB/T 16552—2017 Table A.3 “Freshwater Cultured Pearl”; GB/T 18781—2023 3.2.2; CIBJO Pearl Book 2024 4.4.1.1.2 |
| 背角无齿蚌淡水珍珠Simplified Chinese | narrower name (variety or subtype) | matched automatically | no restriction recorded | GB/T 18781—2023 3.2.2 |
| 褶纹冠蚌淡水珍珠Simplified Chinese | narrower name (variety or subtype) | matched automatically | no restriction recorded | GB/T 18781—2023 3.2.2 |
| annotation only, never as the product name (1) | ||||
| Biwa cultured pearlEnglish | narrower name (variety or subtype) | matched automatically | annotation only, never as the product name | CIBJO Pearl Book 2024 §5.22 “Biwa cultured pearl”; GB/T 16552—2017 5.1.2.3 c); GB/T 16552—2017 5.1.1 c) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 淡水養殖真珠 (not yet checked for this body — the entry's own Japanese name is shown)
- Chinese formal name
- 淡水养殖珍珠 (GB/T 16552—2017 Table A.3, row “Freshwater Cultured Pearl”)
- Mineralogical name
- Cultured pearl formed in a freshwater mollusc
- Trade names and synonyms
- Biwa cultured pearl (narrower name (variety or subtype); annotation only, never as the product name) · Soufflé freshwater cultured pearl (narrower name (variety or subtype)) · Freshwater Pearl (short form; conditional name)
Four-language names
- 简体中文
- 淡水养殖珍珠
- 繁體中文
- 淡水養殖珍珠
- English
- Freshwater Cultured Pearl
- 日本語
- 淡水養殖真珠
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
- Organic or biogenic material
- Mineral chemical class
- Not applicable
- Construction or treatment status
- Cultured formation; treatments recorded separately
Treatments listed by standards
For Freshwater Cultured Pearl, this site applies the Cultured Pearl (Pearl) row of GB/T 16552—2017, Annex B, Table B.1 to classify optimization and treatment: bleaching is optimization; dyeing is treatment; irradiation is treatment.
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 registered material facts for Freshwater Cultured Pearl, the chemical composition is specific to the freshwater pearl entry: relatively enriched in Mn and other trace elements, with less Sr, S, Na, Mg and others. The remaining values are registered by the cited clause for cultured pearl (the whole class), not measured on Freshwater Cultured Pearl alone: overall structure an aggregate whose inorganic part is radially arranged, aragonite being orthorhombic and calcite trigonal, with the organic part amorphous; Mohs hardness 2.5–4, cleavage usually not visible in aggregates; optical character aggregate; refractive index 1.53–1.68, noted as a spot-method reading and a common value rather than an absolute limit, with the clause having finer sub-ranges and the overall value registered; birefringence not measurable on an aggregate; when untreated, pleochroism is not measurable on an aggregate, on stability it effervesces on contact with acid, and the quality factor (lustre) is 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 Freshwater 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 Freshwater Cultured Pearl (how to read class-level values).
Definition
Freshwater Cultured Pearl: cultured pearls produced in molluscs (mussels) in freshwater, e.g., Hyriopsis schlegeliii (9.32), Hyriopsis cumingii (9.31) and Megalonaias nervosa (9.42).
CIBJO Pearl Book 2024
- Qualification
CIBJO trade definition from an institutional manual, not a national standard. The English text quotes the full definition at §5.77 of the Pearl Book 2024.
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.77, p.30 (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Freshwater Cultured Pearl — composition (chemistry): relatively rich in trace elements such as Mn, and relatively poor in Sr, S, Na and Mg.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 Chemical composition · Freshwater pearl (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Structure
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater 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
Freshwater Cultured Pearl — quality factor (shape and size): perfectly round (A1) ≤3.0%; round (A2) ≤8.0%; near-round (A3) ≤12.0%; short oval (B1) ≤20.0%; long oval (B2) >20.0%; high button (C1) ≤20.0%; low button (C2) >20.0%; baroque (D): usually uneven, no obvious symmetry (no percentage given).
GB/T 18781—2023
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Measurement condition
- GB/T 18781—2023 §6.2 and §6.3: maximum and minimum dimensions measured with a gauge graduated to 0.02 mm or finer; diameter difference X=(dmax−dmin)/d×100, one decimal place
- Qualification
For short oval (B1) and high button (C1) the standard gives only an upper limit (≤20.0%) and no lower limit. The button class must also be symmetrical with one or both sides nearly flat (Table 1, note b). Long oval includes drop and pear shapes (note a).
Source & check 2026-09-26
- Source
- GB/T 18781—2023 Cultured pearl grading (GB/T): §4.3 Table 1 (freshwater column), §6.3 (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
- Biwa cultured pearl
a freshwater beaded or non-beaded cultured pearl produced in Lake Biwa, Japan, using the freshwater bivalve mollusc Hyriopsis schlegeliii (9.32). See also 5.203.
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.22, p.24
- Soufflé freshwater cultured pearl
a type of baroque freshwater cultured pearl (5.77) that forms around “mud” inserted into an existing cultured pearl sac (5.54) after the 1st harvest in some Chinese mussels. When drilled the interior is usually cleaned out and becomes hollow. The drilled and cleaned examples are usually very light for their size. These are ‘atypical bead cultured pearls’ (5.19).
CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.184, p.43
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): §9.16 Cristaria plicata · §9.31 Hyriopsis cumingii · §9.32 Hyriopsis schlegelii · §9.34 Lamellidens marginalis · §9.42 Megalonaias nervosa · §9.81 Triangleshell pearl mussel
Testing and market
Identification and market for Freshwater Cultured Pearl: CIBJO's laboratory rules place freshwater cultured pearls under pearl; identification is covered in the pearl entry, and the list of required methods is on the laboratory testing page. The distinction identification can make is that untreated freshwater cultured pearls have a lower density than most natural freshwater pearls. This lower-density lead comes from GB/T 16553—2017.
The CIBJO laboratory protocol covers Freshwater Cultured Pearl under “Pearl” (§6.2.11): see identification on the Pearl entry; the required tests are listed on the CIBJO laboratory protocol table for Pearl.
How far testing can go
Freshwater Cultured Pearl — how far testing can go (separation): Its density is lower than that of most natural freshwater pearls
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.2 Density · Freshwater cultured pearl (locator checked 2026-09-28)
- 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.
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: Pearl Description.
- CIBJO – The World Jewellery Confederation. The Pearl Book (Blue Book), 2024.
- 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 (Freshwater 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 Freshwater 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.