On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Commercial / trade name · Natural identity; treatment status unknown
Mi Yu
A quartzose jade trade name in GB/T 34098-2017 Annex A Table A.1, grouped in one merged cell with other trade names and not matched to any single basic name (quartzose jade, quartzite jade, chalcedony, agate or jasper). The standard does not mention the name outside Table A.1.
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 Mi Yu forms and what gives its colourFormation setting, process and timescale; where its colour and optical effects come from, each finding graded and sourced
- Caring for and wearing Mi YuDurability indicators and wearing advice
- Hardness, density and refractive index of Mi YuEach value with its source and check date
- Mi Yu 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?
- Name origin and history of Mi YuWhere the name comes from
- Listing and disclosing Mi YuThe 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
Mi Yu is a locality-based trade name for quartzose jade from Henan (the Mixian/Xinmi area); its parent material is quartz/chalcedony (cryptocrystalline to macrocrystalline SiO2). Quartz may form where silica carried in migrating solutions accumulates slowly and deposits in fractures and cavities; in volcanic voids, silica-rich fluids penetrate via microfissures or infiltration channels and fill the cavity cyclically from rim to center, producing banded chalcedony and, at the center, macrocrystalline quartz. Its formation is thus the precipitation and void-filling of silica-bearing fluids, which the name alone cannot establish.
Scope: Applies to the origin of the underlying material of the quartzose jade (quartz / chalcedony) referred to by the origin trade name 'Mi Yu'; does not constitute an identification conclusion for a specific sample or locality.
Sources G&G Spring 1982 · G&G Fall 2013 · Handbook of Mineralogy +1
Where it forms
Silica-bearing migrating-solution/hydrothermal setting: rock fractures and cavities, and vesicles/vugs (geodes) in volcanic rocks
Sources G&G Spring 1982 · G&G Fall 2013 · Handbook of Mineralogy
How it forms, step by step
Silica-bearing fluids migrate through the rock system.
The silica-rich fluids penetrate rock voids and cavities through microfissures or infiltration canals.
The fluids fill the cavity cyclically from rim to center, producing banded chalcedony (cryptocrystalline quartz).
Macrocrystalline quartz continues crystallizing at the void center, building the quartzose jade body.
Link to appearance
The semi-translucent massive look comes from the aggregate structure of cryptocrystalline quartz (chalcedony); banding reflects cyclic fluid filling, and color relates to chemical or particulate inclusions in the quartz rather than to the name.
Sources Handbook of Mineralogy · GIA Jade Description
Timescale
The source describes quartz formation on a 'geologic time span' and gives no absolute age for Mi Yu or its parent material.
Sources G&G Spring 1982 · G&G Fall 2013 · Handbook of Mineralogy +1
Related base materials
- Quartzose jade (quartz/chalcedony): Mi yu is an origin trade name for quartzose jade from the Mi yu producing area in Henan; the underlying material is quartz/chalcedony (SiO2), not an independent mineral species.
Supporting findings
Quartz can form by slow precipitation and accumulation of silica from migrating solutions; in volcanic voids, silica-rich fluids fill cyclically from rim to center to form banded chalcedony.
Evidence grade AScope: Generic formation of the parent material (quartz/chalcedony); not unique to the name Mi Yu.
Quartz occurs in hydrothermal veins (epithermal to alpine), is characteristic of granites and granite pegmatites, and occurs in sandstones and quartzites.
Evidence grade BScope: Generic occurrence of quartz; not the occurrence of any specific Mi Yu locality.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Xinmi, Zhengzhou, Henan, ChinaPeer-reviewed text names the Miyu deposit in Xinmi
Sources Acta Petrologica et Mineralogica (2024)
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.
Causes of colour and optical effects
Quartz color can come from chemical or particulate inclusions, ranging from colorless and white to rose-red, yellow, green, blue, brown, and black, and may be zoned or mottled.
Evidence grade BScope: Generic color mechanism of quartz; does not assert the specific colorant of any Mi Yu specimen.
Sources Handbook of Mineralogy
Where the name comes from
The origin of the locality trade name "Mi Yu" itself is not given in the cited sources. The etymology below belongs to the underlying mineral quartz: its name is of obscure origin in the Middle Ages, first applied to gangue in Saxony, Germany. This etymology belongs to the underlying mineral, not to the name "Mi Yu" itself.
Evidence grade BScope: The etymology explains only the origin of the name; it does not establish the material's composition, locality, naturalness, or treatment.
Sources Handbook of Mineralogy
Other research findings
Mi Yu is a locality/trade name and does not constitute an independent mineral or material identity; the word 'jade' has historically been misapplied to a range of jade-like gems and ornamental materials.
Evidence grade BScope: Distinguishes the name from material identity; not specimen identification or provenance.
Sources GIA Jade Description
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- GB/T 34098-2017 and GB/T 16552-2017 are recommended (non-mandatory) national standards whose full text is not freely obtainable; the official free preview does not cover them. This record could not verify their clause text, so it makes no assertion about the specific classification, entry, or table position of this locality trade name in those standards.
- The sources give no absolute age for Mi Yu or its parent material.
- Quartz occurrence and color mechanisms are generic parent-material facts; the sources do not attest a Mi Yu locality or specimen specifically, and they must not be presented as unique to this trade name.
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
- Quartzose jade (trade name: Mi Yu)
GB/T 34098—2017 Table A.1, §6 b)
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
"Mi Yu" is a market name rather than a mineral species name; before using it, verify: Trade name rather than a mineralogical species name. Actual material is unverified.
What this means for you
Before buying, check the recommended listing name "Quartzose jade (trade name: Mi Yu)" 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
- Trade name rather than a mineralogical species name.
- Actual material is unverified.
- Suggested listing name
- Quartzose jade (trade name: Mi Yu)
Care and wear
No institutional care guidance is registered for this material yet; below are its durability indicators and general guidance.
Durability and wearing
Numbers in curly braces, such as {111}, are crystallographic face symbols (Miller indices): each marks a set of crystal faces or cleavage planes. They are reproduced as written in the cited source.
Toughness
tough when massive
Cleavage
Cleavage very rarely observable; poor on {1011}, {0111}, {1010} and others; rhombohedral parting
Daily wear
Hardness 7 resists scratching by ordinary metal and grit, and massive material has good toughness, so it is relatively durable for daily wear; however a hard impact can still chip it, and sudden temperature changes should be avoided to prevent cracking.
Care
Warm water with mild soap and a soft brush suffices; rinse and dry with a soft cloth. For dyed, resin-impregnated or fractured treated material, avoid ultrasonic/steam cleaning and acid washes, and avoid prolonged heat or sunlight.
General guidance: LumaLark's general guidance inferred from the material's properties (hardness, toughness, cleavage); not text from the cited source, and not a guarantee for any specific piece.
Scope: This field describes the material's general properties and is not a finished-product durability promise; it gives no warranty of any specific piece's durability or safety, and the durability of treated (filled, dyed, coated) or composite/assembled material must be assessed separately.
VerifyNames, standards, technical facts, clauses and sources
Names
Trade and mineralogical namesIn GB/T 34098—2017 Table A.1, Mi Yu is listed as a quartz jade trade name that is not used on its own; Table A.1 places Mi Yu in a single merged cell with quartzite jade, chalcedony, agate and jasper, and the original does not specify its basic name, which must first be established by testing, with the note “trade name: Mi Yu” added. Recommended listing nameThe suggested listing name is quartz jade (trade name: Mi Yu). Trade and mineralogical namesThe mineralogical name is quartz jade sold under the trade name Mi Yu (GB/T 34098—2017 Table A.1). Names in four languagesThe Simplified and Traditional Chinese names are the same, the English is Mi Yu, and the Japanese is still to be checked; the GSJ (Japan) formal name is marked as still to be checked, the GSJ wording is not yet verified by this site, and the name shown is the entry's own Japanese name. Institution usageAmong GIA, FTC, CIBJO and Gem-A, the FTC and CIBJO texts have no wording for Mi Yu (checked), and GIA and Gem-A are unchecked; the Mi Yu shown for bodies without a record is the entry's own English name and does not represent their position.
- GSJ (Japan) formal name
- 密玉（待核） (not yet checked for this body — the entry's own Japanese name is shown)
- Trade name listed in the GB/T standard (not used on its own)
- 密玉 (GB/T 34098—2017 Table A.1; basic name not specified in the original — identify the material first)
- Mineralogical name
- Quartzose jade sold under the trade name Mi Yu (GB/T 34098 Table A.1)
Four-language names
- 简体中文
- 密玉
- 繁體中文
- 密玉
- English
- Mi Yu
- 日本語
- 密玉（待核）
GB/T 34098 trade names
- Position in Table A.1
- 密玉 Mi Yu sits in the cell shared by quartzite jade, chalcedony, agate and jasper; the original does not say which one
- How to name it
- The original gives no basic name: identify the material first, then add the note “trade name: 密玉 Mi Yu”
The full table and naming rule are on the Quartzose Jade page.
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Quartz and chalcedony materials
- Identity tier
- Commercial / trade name
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
Among the registered material facts for Mi Yu, chemical composition is registered in the cited clause for quartzose jade (the whole class) and is not repeated on the Mi Yu page; see the material facts on the Quartzose Jade entry. Values taken for quartzose jade (the whole class) are registered as Mohs hardness 6–7, density 2.53–2.72 g/cm³ and refractive index 1.53–1.55. GB/T 34098—2017 also notes that Mohs hardness is sometimes below 6–7, as low as 5.5, and that density sometimes falls outside 2.53–2.72 g/cm³, as low as 2.48 g/cm³ or as high as 2.95 g/cm³. This site notes that hardness alone does not amount to any advice on everyday wear. This site notes that the registered density is the main range and cannot be used as a threshold for deciding a material's identity. Mohs hardness, density and refractive index are all read as values for quartzose jade (the whole class), not measurements of Mi Yu on its own.
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: these whole-class features are given in the cited clause for quartzose jade (the whole class), so they are not repeated on the Mi Yu page; see the material facts on the Quartzose Jade entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Mi Yu (how to read class-level values).
Durability
Mi Yu — Mohs hardness: 6–7
GB/T 34098—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
- quartzose jade (the whole class)
- Qualification
GB/T 34098-2017 §3.1 notes that hardness may sometimes fall to 5.5. Hardness alone does not support any everyday-wear advice.
Source & check 2026-09-26
- Source
- GB/T 34098—2017 Quartzose jade — Classification and nomenclature (GB/T): §3.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Mi Yu — density: 2.53–2.72 g/cm³
GB/T 34098—2017
- Does this standard apply
- applies to this entry
- What this covers
- quartzose jade (the whole class)
- Qualification
GB/T 34098-2017 §3.1 notes that values may sometimes fall to 2.48 or rise to 2.95 g/cm³. The registered range is the main range, not a cut-off for identifying the material.
Source & check 2026-09-26
- Source
- GB/T 34098—2017 Quartzose jade — Classification and nomenclature (GB/T): §3.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Mi Yu — refractive index: 1.53–1.55
GB/T 34098—2017
- Does this standard apply
- applies to this entry
- What this covers
- quartzose jade (the whole class)
Source & check 2026-09-26
- Source
- GB/T 34098—2017 Quartzose jade — Classification and nomenclature (GB/T): §3.1 (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): 1.54 / 2.62; Closest values: 1Charoite 1.554 / 2.66, 2Changhua Stone 1.56 / 2.6, 3Balin Stone 1.56 / 2.55, 4Shoushan Stone 1.56 / 2.7, 5Bamboo Coral 1.57 / 2.65
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
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.
- AQSIQ / SAC (China). GB/T 34098—2017 Quartzose jade — Classification and nomenclature.
- 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 Quartz on this site: 74 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Mi Yu) is marked.
- Quartz
Sub-entries (57)
- Agate
Sub-entries (1)
- Amethyst
- Ametrine
- Aventurine Quartz
- Aventurine Quartz / Green Aventurine
- Banded Agate
- Black Agate
- Bloodstone / Heliotrope
- Blue Lace Agate
- Carnelian
- Chalcedony
Sub-entries (2)
- Chrysoprase
- Citrine
- Clear Quartz / Rock Crystal
- Coated Quartz
- Colourless to White Quartz (brand name: Azeztulite)
- Crazy Lace Agate
- Dendritic Agate
- Dyed Agate (Treated: dyed)
- Elestial Quartz / Skeletal Quartz
- Eye Agate
- Flower Agate / Cherry Blossom Agate
- Green Quartz
- High-clarity quartz with golden needle-like inclusions
- Included Quartz
- Jasper
Sub-entries (1)
- Madeira Citrine
- Malachite Agate
- Morion / very dark Smoky Quartz
- Moss Agate
- Moss Chalcedony
- Multi-inclusion Quartz
- Onyx (banded chalcedony)
- Phantom Quartz
- Prase
- Prasiolite / Green Quartz
- Quartz Cat’s-eye
- Quartz claimed to be from the Himalayas
- Quartz Crystal
- Quartz with dark needle-like inclusions
- Quartz with fine fibrous inclusions
- Quartz with flower-like inclusions
- Quartz with golden needle-like inclusions
- Quartz with green needle-like inclusions
- Quartzite Jade
- Quartzose Jade
Sub-entries (9)
- Red Agate
- Rock Crystal
- Rose Quartz
- Rutilated Quartz
- Sard
- Sardonyx
- Silicified Asbestos
Sub-entries (2)
- Hawk’s Eye
- Tiger’s Eye
Sub-entries (1)
- Smoky Quartz
- Smoky Quartz (brown variety)
- Strawberry Quartz
- Yellow-green Quartz
- Agate
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Quartz and chalcedony materials | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Mi Yu 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.