On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Trade name: colour / appearance variety · Natural identity; treatment status unknown
Black Nephrite
A commercial name for the black colour subvariety under Hetian Yu; the material must be confirmed by testing as tremolite–actinolite Nephrite. 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 Black Nephrite forms and what gives its colourFormation setting, process and timescale; where its colour and optical effects come from, each finding graded and sourced
- How to identify Black NephriteHow far lab testing can go
- Treatments and enhancements of Black NephriteThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Black NephriteCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of Black NephriteEach value with its source and check date
- Black Nephrite 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 Black NephriteThe listing name to use; what must be disclosed before sale
- Standard clauses that define Black NephriteWhich clause defines it, each cross-checked
What we cannot conclude
- Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.
- Geographic origin, unless an origin report accompanies the item.
- Price, rarity or investment value: this wiki covers naming and disclosure only.
Material research: formation, causes and history
What authoritative sources say about how this material forms, what causes its colour and optical effects, where its name comes from and how people have used it. Each statement carries an evidence grade and its sources; it describes the material in general, not any specific piece.
How it forms
Moyu denotes black nephrite. Its material basis is a fine-grained fibrous (interlocking/felted) aggregate of tremolite-actinolite series amphibole of metamorphic origin, formed chiefly by metasomatism (hydrothermal metamorphism): silica-rich fluids replacing dolomite-rich rocks, or calcium-rich fluids reacting with serpentinites, with tremolite and ferro-actinolite as end members. No parent-level fact is claimed as unique to this colour name.
Scope: Applies to the material-level genetic description of "black nephrite" as a Chinese colour-based trade name for nephrite; its colour boundaries are not treated as verifiable standard clauses.
Sources G&G Summer 2023 · GIA Jade Description
Where it forms
Contact-metamorphic setting: Ca-Mg siliceous sediments heated by an igneous body.
Sources G&G Summer 2023
Regional metamorphism / greenschist facies: low-grade metamorphism of ultramafic or magnesium-carbonate rocks.
Sources G&G Summer 2023
Hydrothermal metasomatic (hydrothermal-metamorphic) setting: silica-rich fluids replacing dolomite-rich rocks, or calcium-rich fluids reacting with serpentinites.
Sources G&G Summer 2023
How it forms, step by step
Protolith in place: dolomite-rich / magnesium-carbonate rock or ultramafic rock exists in contact with an igneous body or fluid system.
Fluid metasomatism: silica-rich fluid enters dolomitic rock, or calcium-rich fluid reacts with serpentinite (metasomatism).
Tremolite-actinolite crystallises: amphibole forms via the reaction 5 dolomite + 8 aqueous silica + water → tremolite + 3 calcite + 7 aqueous carbon dioxide.
Fibrous interlocking (felted) aggregate develops: fine fibrous crystals interlock into a dense, tough jade.
Link to appearance
The fine interlocking fibrous texture makes nephrite exceptionally tough and carvable and gives its translucent-to-opaque, waxy look; colour varies with composition and iron content, generally more muted than jadeite.
Sources G&G Summer 2023 · GIA Jade Description
Timescale
The available sources give no absolute geological age or date for nephrite formation.
Sources G&G Summer 2023 · GIA Jade Description
Related base materials
- Nephrite: Fibrous aggregate of amphiboles of the tremolite–actinolite series (the underlying material of this material family)
Supporting findings
Nephrite forms by hydrothermal metamorphism (metasomatism): silica-rich fluids infiltrate dolomite-rich rocks, or calcium-rich fluids react with serpentinites; the dolomite route can be written 5 dolomite + 8 aqueous silica + water → tremolite + 3 calcite + 7 aqueous carbon dioxide.
Evidence grade AScope: Describes the natural genesis of the underlying material (tremolite-actinolite nephrite) only; it does not establish a specimen's origin, treatment, or colour subcategory.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Hotan Prefecture, Xinjiang, ChinaWithin Xinjiang: graphite-coloured black nephrite mainly from Hetian, not found in Qiemo or Ruoqiang
Sources Gems & Gemology Summer 2020
- Dahua County, Hechi, Guangxi, ChinaGuangxi black nephrite is mainly actinolite/ferro-actinolite, not graphite-coloured
Sources Gems & Gemology Summer 2019
These are localities recorded by authoritative sources, not an origin finding for any individual piece. The CIBJO Gemstone Book (2022, §4.2.3) says a place of origin names where a gem was mined or harvested, is a matter of opinion, does not imply a level of quality, and that cutting, processing or exporting centres must not be used to imply origin. See how far testing can go on this page, the origin determination guide and the overview of recorded localities.
Causes of colour and optical effects
Moyu denotes black nephrite; nephrite can indeed be black. However, which dark inclusions or colourants cause the black is not given in the cited sources and requires testing; graphite or any specific inclusion must not be assumed.
Evidence grade BScope: Confirms nephrite can be black only; it does not assume a cause for the black colour (the sources do not give one).
Sources GIA Jade Description
Other research findings
Nephrite is not a single crystal but a fibrous aggregate, interlocking or felted, whose dominant component is amphibole of the tremolite–actinolite series; its composition ranges across the end members from ferro-actinolite Ca2Fe5Si8O22(OH)2 to tremolite Ca2Mg5Si8O22(OH)2.
Evidence grade AScope: Describes nephrite's mineral composition range only; it does not establish a specimen's origin, treatment, or colour.
This name is a colour/variety trade name under the Chinese nephrite system, denoting a tremolite-actinolite material; without the full text of the relevant standard this record makes no clause-level definition of its colour boundary and does not treat it as an independent mineral species.
Evidence grade BScope: This name is a Chinese nephrite colour trade name, not an independent mineral species; no GB/T clauses or tables are invented here (its full text is not obtainable).
Sources GIA Jade Description
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The full text of GB/T 16552 and similar standards is not obtainable, so the clause-level basis of this colour subcategory could not be verified; no clauses or tables are invented.
- The specific colouring mechanism of this subcategory is not given in the available sources and requires testing; none is asserted.
- Colour boundaries can be continuous in the trade and do not replace compositional identification.
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
- Black Nephrite jade
GB/T 16552—2017 Table A.2 “Hetian Yu,Nephrite” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.154 “Nephrite”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Filled / Fracture-filled (via parent material), Dyed (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
"Black Nephrite" is a market name rather than a mineral species name; before using it, verify: Trade name rather than a mineralogical species name.
Evidence
- GB/T · Table A.2, row 和田玉 (Hetian Yu / Nephrite)
What this means for you
Before buying, check the recommended listing name "Black Nephrite jade" 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
- Trade name rather than a mineralogical species name.
- Suggested listing name
- Black Nephrite jade
Care and wear
The item-by-item care advice that the GIA Care and Cleaning Guide gives for the whole class, and so for Black Nephrite, is set out in full under care on the Nephrite 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.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Dyeing | — | — | Treatment | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Nephrite)
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
Standard and listing namesThe Chinese formal name for Black Nephrite is given in GB/T 16552—2017 Table A.2; its identity level is trade name: colour/appearance variety, and the mineralogical name is written as Black nephrite (GB/T colour subcategory). The suggested listing name is black nephrite (Black Nephrite). Names in four languagesNames are given in Simplified Chinese, Traditional Chinese, English (Black Nephrite) and Japanese. Institution usageOn authority wording, FTC and CIBJO have been checked and their texts contain no wording for the name Black Nephrite; the wording of GIA and Gem-A is not yet verified. The English name shown for bodies without a recorded wording comes from the entry itself and does not represent their position. Japanese namesThe wording used by GSJ (Japan) for this name is not yet verified, and the entry has its own Japanese name.
- GSJ (Japan) formal name
- 墨玉 (not yet checked for this body — the entry's own Japanese name is shown)
- Chinese formal name
- 墨玉 (GB/T 16552—2017 Table A.2)
- Mineralogical name
- Black nephrite (GB/T colour subcategory)
Four-language names
- 简体中文
- 墨玉
- 繁體中文
- 墨玉
- English
- Black Nephrite
- 日本語
- 墨玉
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Jade materials
- Identity tier
- Trade name: colour / appearance variety
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
Black Nephrite is handled under the nephrite row of GB/T 16552—2017 Annex B Table B.1 as applied by this site: filling, with the definitions of the filling grades on this site's treatments page; and dyeing, classed as a treatment. GB/T 16552—2017 Table B.1 does not list black nephrite; this is this site's application of the nephrite row. The nephrite row also has an effect column, given in full in the nephrite entry; the notes to Table B.1 and the definitions of the filling grades are on this site's treatments page.
GB/T 16552-2017, Annex B, Table B.1
Under the “Nephrite” row of Table B.1: Filling Graded — see §5.4.1, Table 1; Dyeing Treatment. The full row, with the effect column, is on the Nephrite 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 Black Nephrite, structure, Mohs hardness, cleavage, optical character and lustre are registered for nephrite as a whole (regardless of origin): the structure is a crystalline aggregate, often fibrous; Mohs hardness is 6–6.5; tremolite itself has two perfect cleavages, which are generally not visible in the aggregate; optical character is an anisotropic aggregate; and untreated Black Nephrite has a vitreous to greasy lustre. Density of 2.9–3.1 g/cm³ and refractive index of 1.6–1.641 are also registered for nephrite as a whole (regardless of origin); per this site's notes, the density range is derived from the clause value of 2.95 with a tolerance of +0.15/−0.05, and the refractive index range from the clause value of 1.606–1.632 with a tolerance of +0.009/−0.006, and the clause has finer sub-ranges of which the overall value is taken. Untreated Black Nephrite has a greyish black to black body colour and contains microcrystalline graphite; this site notes that the colours of other varieties in Chapter 5 of GB/T 16553—2017 also include black or blackish tones.
Registered material facts
Each row carries its own source and check date and can be cited on its own; “—” means the cited source gives no value, not “none”.
Chemical composition, luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for nephrite as a whole (not one source), so they are not repeated on the Black Nephrite page; see the material facts on the Nephrite entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Black Nephrite (how to read class-level values).
Structure
Black Nephrite — structure (overall): a crystalline aggregate that is often fibrous
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Black Nephrite — Mohs hardness: 6–6.5
GB/T 16553—2017
Reference points on this site: Talc 1–3, Fluorite 4, Apatite 5–5.5, Orthoclase 6–6.5, Topaz 8, Diamond 10 (Source: GB/T 16553—2017); Gypsum 1.5–2, Calcite 3, Quartz 7 (Source: Handbook of Mineralogy); Corundum 9 (Source: GIA Gem Encyclopedia (care guide))
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Black Nephrite — cleavage: Tremolite crystals cleave perfectly in two directions; aggregates usually have no cleavage.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Black Nephrite — density: 2.9–3.1 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
- Qualification
The clause we cite gives 2.95, with a stated tolerance of +0.15 / -0.05. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Black Nephrite — optic character: anisotropic aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Black Nephrite — refractive index: 1.6–1.641
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
- Qualification
The clause we cite gives 1.606–1.632, with a stated tolerance of +0.009 / -0.006. The range shown here is worked out from that.
- General note
- the clause has finer ranges
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Black Nephrite — birefringence: not measurable on an aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Black Nephrite — pleochroism: not measurable on an aggregate
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Black Nephrite — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Black Nephrite — body colour: greyish black to black; contains microcrystalline graphite.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
In chapter 5 of GB/T 16553—2017, the colour entries of Hematite, Howlite, Charoite and other variety clauses also name black or a blackish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 Colour · Black nephrite (moyu) (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- chatoyancy
Quality factors
Black Nephrite — quality factor (lustre): vitreous to greasy
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- nephrite as a whole (not one source)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.2 (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.
This material (RI / SG midpoints): 1.621 / 3; Closest values: 1Danburite 1.633 / 3, 2Amblygonite 1.607 / 3.02, 3Dushan Yu / Dushan Jade 1.63 / 2.9, 4Prehnite 1.625 / 2.88, 5Lazulite 1.627 / 3.12
Show the full chart (330 registered materials)
Outside the full chart's range, drawn as triangles at the edge (RI / SG midpoints): Hematite 3.045/5.12, Synthetic Rutile 2.76/4.26, Rutile 2.753/4.23, Synthetic Moissanite 2.67/3.22
Testing and market
The CIBJO laboratory protocol covers Black Nephrite under “Nephrite” (§6.1.54): see identification on the Nephrite entry; the required tests are listed on the CIBJO laboratory protocol table for Nephrite.
How far testing can go
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
At clause level, Black Nephrite corresponds to GB/T 16552—2017 Annex A, with the English term Black Nephrite; the definition points to Table A.2 “Hetian Yu, Nephrite” in GB/T 16552—2017, and the full description is on the Hetian Yu (nephrite) entry. The cross-check concludes that GB/T lists the name directly, while no standalone CIBJO entry under the same name was found.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Black Nephrite | GB/T 16552-2017 Annex A | For the full description, see Table A.2 “Hetian Yu,Nephrite” in GB/T 16552—2017. | Listed directly by GB/T; CIBJO carries no standalone entry under the same name. |
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.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- Geological Survey of Japan, AIST (Japan). Museum mineral specimens, browse by classification.
Further reading
Related entries and topic cluster
Parent entry and related pages on this site. Rows marked “Planned” are suggested new content and have no link yet.
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| Page | Content | Status |
|---|---|---|
| Browsing family | Jade materials | Live |
| Treatments recorded for this material | Filled / Fracture-filled (via parent material), Dyed (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Black Nephrite entry are maintained by the LumaLark wiki and matched one by one to the standard clauses or institutional sources they cite: every fact carries its source (with a clause or page locator) and a check date, so it can be traced back to the original; clause-level definitions also carry a cross-check result. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.