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
Dendritic Agate
Chalcedony containing tree-like inclusions of manganese and iron oxides; the "branches" are an inclusion pattern, not plant fossils. 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 Dendritic Agate forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify Dendritic AgateIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Dendritic AgateThe enhancements and treatments the GB/T and JJA/AGL tables list
- Hardness, density and refractive index of Dendritic AgateEach value with its source and check date
- Dendritic 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 Dendritic 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
Dendritic agate is a market name for agate or chalcedony containing tree-like (dendritic) inclusions, closely related to water-grass agate and 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 tree-like pattern is drawn by dendritic mineral inclusions growing along fractures or between layers. Authorities show agate/chalcedony may contain needle- and dendrite-like metal-oxide inclusions such as iron oxides, but “dendritic agate” has no authoritative definition and whether the inclusions are manganese or iron oxides requires case-by-case testing.
Scope: Covers the layered mechanism of the siliceous matrix of agate with dendritic inclusions and the nature of the dendritic inclusions; does not constitute a mineralogical definition of the trade name "dendritic agate".
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: oxides grow as dendritic crystals along fractures and between layers.
Sources G&G Fall 2013 · G&G Winter 2015
How it forms, step by step
Silica-rich fluids carrying metal elements penetrate a volcanic void along microfissures.
Sources G&G Fall 2013 · G&G Winter 2023 · G&G Winter 2015
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 inclusions along fractures and between layers, creating the “tree” pattern.
At the final stage idiomorphic quartz may crystallize in the void centre.
Link to appearance
Dendritic metal-oxide inclusions grow along fractures and between layers, producing tree-like or fern-like internal patterns; colours are typically black, brown or red-brown.
Sources G&G Fall 2013 · G&G Winter 2015
Timescale
The sources give no absolute age or growth duration for dendritic agate or its dendritic inclusions.
Sources G&G Fall 2013
Related base materials
- Chalcedony / agate (microcrystalline quartz, SiO2): commercial-name-of | Dendritic agate is a commercial name for agate or chalcedony containing dendritic (branching) 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.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Central IndiaOnly the item title was retrievable; no state named
Sources Gems & Gemology Fall 2008
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
For dendritic 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) that produce tree-like internal patterns.
Evidence grade BScope: Based on inclusion observations in agate and chalcedony; the composition of dendritic-agate inclusions is not verbatim confirmed.
“Dendritic agate” is a market trade name with no authoritative mineralogical definition; its dendritic inclusions must be confirmed by testing each piece.
Evidence grade CScope: Authorities define agate/chalcedony and general inclusion types but not “dendritic agate.”
Attributing the dendritic inclusions of dendritic agate to manganese oxides lacks direct support in the cited sources, where only iron and titanium oxides are named verbatim.
Evidence grade CScope: The source names hematite, goethite and titanium oxide and lists “Fe, Ti, Mn and others” but does not link manganese directly to dendritic inclusions.
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- “Dendritic agate” has no authoritative mineralogical definition; this record uses general agate/chalcedony mechanisms and general inclusion observations.
- The mineral identity of the dendritic inclusions (manganese vs iron 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
- 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
"Dendritic 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 "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
- 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 Dendritic Agate, the name register records "Dendritic agate", for which no restriction on use as a name is recorded.
Standard and listing namesThe GB/T 16552—2017 naming counterpart for Dendritic Agate is Agate, as the standard does not list the name Dendritic Agate itself; the suggested listing name is Dendritic Agate. Trade and mineralogical namesDendritic Agate is itself a trade name, with the identity tier colour/appearance variety. Names in four languagesThe four-language names are the Simplified and Traditional Chinese names, English Dendritic Agate and the Japanese name. The GSJ (Japan) formal-name field shows the entry's own Japanese name, as GSJ's wording for this name is not yet verified by this site. Trade and mineralogical namesThe recorded English market name is Dendritic agate, and the mineralogical name refers to chalcedony with dendritic inclusions of manganese and iron oxides. Institution usageFor authority wording, the FTC text on file has no wording for this name (checked), and GIA, CIBJO and Gem-A wording is unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position.
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) | ||||
| Dendritic 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
- デンドリティックアゲート (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 manganese/iron oxide dendrites
Four-language names
- 简体中文
- 树枝玛瑙
- 繁體中文
- 樹枝瑪瑙
- English
- Dendritic Agate
- 日本語
- デンドリティックアゲート
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
Dendritic Agate is not listed separately in GB/T 16552—2017, Annex B, Table B.1; this site applies the Chalcedony (Agate/Jasper) row of Table B.1: heating, classed as optimization; filling, graded; dyeing, classed as optimization. The full row of Table B.1, with the effect column, is on the Chalcedony page; what Table B.1 is and how the filling grades are defined are explained on the Gem treatments page.
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
Among the registered material facts for Dendritic Agate, the items marked as category values come from GB/T 16553—2017 Gems — Testing and are written for chalcedony (including agate and jasper, the whole category), not data measured on dendritic agate alone. Registered under chalcedony (including agate and jasper, the whole category): a cryptocrystalline aggregate, which may be compact and massive, spherulitic, radiating or microfibrous; Mohs hardness 5–7, no cleavage; density 2.5–2.77 g/cm³; optically an anisotropic aggregate; refractive index 1.535–1.539, this site noting that the clause also has finer sub-ranges and the overall value is taken; birefringence cannot be measured in aggregates; pleochroism, when untreated, cannot be measured in aggregates; among optical effects, iridescence and cat's-eye effect may be seen; among quality factors, the lustre when untreated is vitreous to greasy. Category-wide features such as chemical composition, fluorescence, UV-Vis spectrum, infrared spectrum and magnification are written for chalcedony (including agate and jasper, the whole category); see the chalcedony entry.
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 Dendritic 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 Dendritic Agate (how to read class-level values).
Structure
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
Dendritic 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
The CIBJO laboratory protocol covers Dendritic 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
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 (Dendritic 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 Dendritic 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.