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
Moss Agate
Chalcedony containing tree-like mineral inclusions, often without banding. Strictly in mineralogy it is not necessarily agate, but the trade still calls it that. 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 Moss Agate forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify Moss AgateIdentification points from the research literature; how far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Moss AgateThe enhancements and treatments the GB/T and JJA/AGL tables list
- Hardness, density and refractive index of Moss AgateEach value with its source and check date
- Moss Agate 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 Moss AgateThe 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
Water-grass agate is a market name for agate or chalcedony containing dendritic, grass- or fern-like inclusions; it is not a distinct mineral species. By the prevailing hypothesis its silica groundmass forms inside a volcanic void as silica-rich fluids fill it in cycles from rim to center. The “water grass” is dendritic mineral inclusions in the silica matrix. Authorities show that agate/chalcedony matrices may contain needle- and dendrite-like metal-oxide inclusions such as iron oxides, but “water-grass agate” has no authoritative definition and whether the inclusions are iron or manganese oxides must be tested case by case.
Scope: Covers the layered mechanism of the siliceous matrix of agate with dendritic inclusions and the metal-oxide nature of the inclusions; does not constitute a mineralogical definition of the trade name "moss agate" (shui cao ma nao).
Sources G&G Fall 2013 · G&G Winter 2023 · G&G Winter 2015
Where it forms
Gas cavities or voids in volcanic rock (e.g. basalt) entered by silica- and metal-bearing fluids along microfissures.
Sources G&G Fall 2013 · G&G Winter 2023 · G&G Winter 2015
Late hydrothermal to supergene setting: iron- and manganese-bearing oxides form dendritic inclusions along fractures and open spaces.
Sources G&G Fall 2013 · G&G Winter 2015
How it forms, step by step
Silica-rich fluids carrying Fe, Mn and other elements penetrate a volcanic void along microfissures.
The fluids fill the void in cycles from rim to center, precipitating the agate/chalcedony groundmass.
Sources G&G Fall 2013 · G&G Winter 2023 · G&G Winter 2015
Metal oxides grow as dendritic, feathery inclusions along fractures and grain boundaries, creating the “water-grass” pattern.
At the final stage idiomorphic quartz may crystallize in the void centre.
Link to appearance
Dendritic or needle-like metal-oxide inclusions in the silica matrix create the water-grass or mossy internal pattern; the colour is typically black, brown or red-brown depending on the oxide species and abundance.
Sources G&G Fall 2013 · G&G Winter 2015
Timescale
The sources give no absolute age or growth duration for water-grass agate or its dendritic inclusions; agate as a class can mature over tens of millions of years, but no specific timescale is stated for this material.
Sources G&G Fall 2013
Related base materials
- Chalcedony / agate (microcrystalline quartz, SiO2): commercial-name-of | Moss agate is a commercial name for agate or chalcedony containing dendritic/moss-like inclusions
Supporting findings
Agate/chalcedony grows in volcanic voids, where silica-rich fluids deposit material in rim-to-centre cycles.
Evidence grade AScope: General agate/chalcedony formation mechanism, applicable to the silica groundmass of such materials.
How it is identified
For moss agate, colour and banding by themselves do not reveal whether the hue is natural or produced by dyeing or heating, so visual appearance cannot settle naturalness or treatment; a trustworthy identification and any treatment ruling call for instrumental examination at a qualified gem laboratory, and this entry is no basis for self-testing.
Evidence grade AScope: Appearance cannot replace identification; naturalness, dyeing or heat treatment must be determined at a qualified gem laboratory, and this entry is not a self-testing basis.
Sources G&G Summer 2014 · CIBJO Gemstone Book 2022
Other research findings
Agate/chalcedony matrices may contain needle- and dendrite-like metal-oxide inclusions such as iron oxides.
Evidence grade AScope: Based on inclusion observations in agate and chalcedony; it cannot be assumed water-grass agate inclusions are the same phase.
“Water-grass agate” is a market trade name with no authoritative mineralogical definition; the exact mineral species of its dendritic inclusions must be confirmed by testing each piece.
Evidence grade CScope: Authorities define agate/chalcedony and general inclusion types but not “water-grass agate.”
Such dendritic inclusions are commonly attributed to iron/manganese oxides, but the cited sources do not verbatim confirm the presence of manganese oxides.
Evidence grade CScope: Mn appears only in the phrase listing “other elements found in the fluids (Fe, Ti, Mn, and others)” and is not directly tied to dendritic inclusions.
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- “Water-grass agate” has no authoritative mineralogical definition; this record uses general agate/chalcedony mechanisms and general inclusion observations.
- The mineral identity of the dendritic inclusions (iron vs manganese oxides) is not confirmed by the cited sources and requires case-by-case testing.
- No absolute age or growth duration is available for this material.
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
- Moss / dendritic Agate
GB/T 16552—2017 5.1.1 c) · CIBJO Gemmological Laboratories Book 2024 §7.2.1.3 “Agate”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated (via parent 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
"Moss Agate" is a market name rather than a mineral species name; before using it, verify: Industry-wide term that does not denote a single species.
What this means for you
Before buying, check the recommended listing name "Moss / dendritic Agate" 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
- Industry-wide term that does not denote a single species.
- Suggested listing name
- Moss / dendritic Agate
Care and wear
No care facts are recorded for this entry itself. Its parent material has care records: see Quartz.
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 |
|---|---|---|---|---|---|
| Heating | — | — | Optimization | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Dyeing | — | — | Optimization | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Chalcedony)
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
Besides Moss Agate, the name register records "Moss agate", for which no restriction on use as a name is recorded.
Standard and listing namesThe GB/T 16552—2017 naming counterpart for Moss Agate is agate, and the name Moss Agate is not listed in the original GB/T 16552—2017; the suggested listing name registered by this site is Moss or dendritic agate. Names in four languagesNames are registered in four languages: Simplified Chinese, Traditional Chinese, English (Moss Agate) and Japanese. Trade and mineralogical namesThe English market name and synonym is Moss agate, and the mineralogical name is chalcedony with dendritic mineral inclusions. Institution usageOn authority wording, of GIA, FTC, CIBJO and Gem-A, the FTC text on file has no wording for Moss Agate (checked), and the wording of GIA, CIBJO and Gem-A is unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. Japanese namesThe Japanese name shown is the entry's own; the wording used by the GSJ (Japan) for it is not yet verified by this site.
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 (1) | ||||
| Moss agateEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- モスアゲート (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)
- 玛瑙 (GB/T 16552—2017 §5.1.1 c))
- Mineralogical name
- Chalcedony with dendritic mineral inclusions
Four-language names
- 简体中文
- 水草玛瑙
- 繁體中文
- 水草瑪瑙
- English
- Moss Agate
- 日本語
- モスアゲート
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
- Trade name: colour / appearance variety
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T 16552-2017, Annex B, Table B.1
Under the “Chalcedony (Agate/Jasper)” row of Table B.1: Heating Optimization; Filling Graded — see §5.4.1, Table 1; Dyeing Optimization. The full row, with the effect column, is on the Chalcedony 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 material facts for Moss Agate on structure, Mohs hardness, cleavage, density, optic character, refractive index, birefringence, pleochroism and quality factor (lustre) are written by the cited clause for chalcedony, including agate and jasper (the whole class), not measured separately for Moss Agate. For chalcedony as a whole class, the structure (overall) of Moss Agate is a cryptocrystalline aggregate, compact and massive, and may also be spherulitic, radial or a microfibrous aggregate; Mohs hardness 5–7; no cleavage; density 2.5–2.77 g/cm³; optic character anisotropic aggregate; refractive index 1.535–1.539, and this site notes that the clause gives finer bands, with the overall refractive index value taken; birefringence not measurable in aggregates. For chalcedony as a whole class, when untreated, pleochroism is not measurable in aggregates and the quality factor (lustre) is vitreous to greasy.
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 chalcedony, including agate and jasper (the whole class), so they are not repeated on the Moss Agate page; see the material facts on the Chalcedony entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Moss Agate (how to read class-level values).
Structure
Moss Agate — structure (overall): a cryptocrystalline aggregate, dense and massive in habit; it may also form spherulitic, radial or finely fibrous aggregates.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Moss Agate — Mohs hardness: 5–7
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
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Moss Agate — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Moss Agate — density: 2.5–2.77 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Moss Agate — optic character: anisotropic aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Moss Agate — refractive index: 1.535–1.539
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
- General note
- the clause has finer ranges
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Moss Agate — birefringence: not measurable on an aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Moss Agate — pleochroism: not measurable on an aggregate
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Moss Agate — optical effect (iridescence): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Moss Agate — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- chatoyancy
Quality factors
Moss Agate — quality factor (lustre): vitreous to greasy
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- chalcedony, including agate and jasper (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.5 (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): 1.537 / 2.63; Closest values: 1Amethyst 1.548 / 2.67, 2Charoite 1.554 / 2.66, 3Changhua Stone 1.56 / 2.6, 4Shoushan Stone 1.56 / 2.7, 5Balin Stone 1.56 / 2.55
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
Under the CIBJO laboratory protocol, laboratory identification of Moss Agate falls under the chalcedony entry; for identification of Moss Agate see identification on the Chalcedony entry, and the list of required methods is on the laboratory testing page. According to the CIBJO record, there is no synthetic Moss Agate on the market.
The CIBJO laboratory protocol covers Moss Agate under “Chalcedony” (§6.1.16): see identification on the Chalcedony entry; the required tests are listed on the CIBJO laboratory protocol table for Chalcedony.
How far testing can go
Moss Agate — synthetic counterpart on the market: No synthetic counterpart of this material is commercially available
CIBJO Gemstone Book 2022
- Treatment state
- any treatment state
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
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
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 (Moss Agate) 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
- 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 |
| Treatments recorded for this material | Heated / Heat-treated (via parent 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 Moss Agate 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.