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
Chrome Chalcedony
Also known asMtorolite
Chalcedony coloured green by chromium. This is a different cause of colour from chrysoprase, whose green comes from nickel-bearing clay inclusions. 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 Chrome Chalcedony 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 Chrome ChalcedonyIdentification points from the research literature
- Caring for and wearing Chrome ChalcedonyDurability indicators and wearing advice
- Hardness, density and refractive index of Chrome ChalcedonyEach value with its source and check date
- Chrome Chalcedony in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Which of GIA, FTC, CIBJO and Gem-A have a name for it on record, and do those agree?
- Name origin and history of Chrome ChalcedonyWhere the name comes from
- Listing and disclosing Chrome ChalcedonyThe 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
Chrome chalcedony (trade name mtorolite) is green chalcedony coloured by chromium; its base is chalcedony (cryptocrystalline quartz, SiO2), and it is not an independent mineral species. Chalcedony is cryptocrystalline silica that commonly forms by cyclic filling of open cavities such as gas cavities of volcanic rocks, precipitating from the wall inward. As to colour, GIA's examination of an African green-to-blue-green chalcedony (trade name Aquaprase) shows that natural green chalcedony can be coloured by chromium (and nickel), with sharp absorption peaks at about 646 nm, 676 nm and 679 nm attributed to chromium. No authoritative source specifically defining 'mtorolite/chrome chalcedony' has been found, so this entry gives only the base chalcedony's composition and occurrence plus the anchorable evidence that chromium colours natural green chalcedony, and flags the name's specific definition as a gap.
Scope: Applies to explaining the identity, composition, occurrence and evidence for chromium colouration of chrome chalcedony as a green chalcedony variety (the host being quartz); not applicable to determining the locality, treatment or value of a specific sample from the name.
Sources G&G Fall 2013 · G&G Winter 2015 · Handbook of Mineralogy
Where it forms
Chalcedony forms in open cavities such as gas cavities of volcanic rocks, filling cyclically from the wall inward.
Sources G&G Fall 2013
Natural green chalcedony coloured by chromium (and nickel) has been reported by GIA (trade name Aquaprase, African origin).
Sources G&G Fall 2013
How it forms, step by step
Silica-bearing fluids precipitate cryptocrystalline silica (chalcedony) in open cavities.
Sources Handbook of Mineralogy
Colouring elements such as chromium (and nickel) in the lattice render the chalcedony green.
Sources Handbook of Mineralogy
Whether a given sample is dominantly chromium-coloured and whether it is treated must be established by testing.
Sources Handbook of Mineralogy
Link to appearance
It appears as a green chalcedony material; but a green appearance alone cannot prove chromium is the chromophore (chromium and nickel can both affect colour).
Sources G&G Winter 2015 · Handbook of Mineralogy
Timescale
The cited sources give no absolute age or growth duration for chrome chalcedony.
Sources G&G Fall 2013 · G&G Winter 2015 · Handbook of Mineralogy
Related base materials
- Chalcedony (cryptocrystalline quartz): Host material; chrome chalcedony is a green chalcedony variety coloured by chromium
Supporting findings
Chalcedony commonly forms in open cavities such as gas cavities of volcanic rocks, cyclically filled inward from the wall by silica-bearing fluids.
Evidence grade AScope: Generic occurrence of chalcedony (the base); not tied to a specific chrome chalcedony locality (e.g. Zimbabwe).
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- ZimbabweZimbabwean material referred to as mtorolite
Sources Gems & Gemology Winter 2009
South America
- Bolivia
Sources Gems & Gemology Winter 2009
Oceania
- Australia
Sources Gems & Gemology Winter 2009
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
Natural green chalcedony can be coloured by chromium (and nickel); sharp absorption peaks at about 646 nm, 676 nm and 679 nm are attributed to chromium.
Evidence grade AScope: Evidence that chromium colours natural green chalcedony (based on GIA testing of an Aquaprase sample); it does not assert the chromophore proportions of any chrome chalcedony sample.
Sources G&G Winter 2015
Where the name comes from
The origin of the variety name "chrome chalcedony" 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 "chrome chalcedony" 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
How it is identified
The colour and inclusion appearance of 'chrome-chalcedony' cannot establish whether a stone is natural, synthetic or treated: quartz varieties that look alike may differ entirely in composition, growth history and treatment, and synthetic and natural quartz share essentially the same composition and physical properties, so the unaided eye cannot separate them. Laboratory identification rests on measurable properties and the division of labour between instruments — a polariscope with a conoscope lens can judge colour-zoning orientation from extinction and optic-axis readings, a refractometer gives refractive-index values, and EDXRF with infrared spectroscopy supplies chemical and structural fingerprints. Limitations: some methods depend on how the stone was cut and on comparison with reference material, and the final conclusion must be issued by an accredited gemological laboratory through testing rather than inferred from appearance.
Evidence grade AScope: Identification and separation points; testing must be performed by an accredited gemological laboratory, and no self-test thresholds are given.
Sources G&G Summer 2014 · CIBJO Gemstone Book 2022
Other research findings
Chrome chalcedony (mtorolite) is green chalcedony coloured by chromium; its base is chalcedony (cryptocrystalline quartz), and it is not an independent mineral species; no authoritative source specifically defining the name has been found, so its specific definition is flagged as a gap.
Evidence grade CScope: An identity-boundary judgement; no authoritative source for the specific definition of 'mtorolite' has been found, hence C.
Sources G&G Winter 2015
Chalcedony is cryptocrystalline silica (SiO2); quartz is stable below 573°C.
Evidence grade BScope: Chemical composition and phase stability of quartz/chalcedony; not a determination of any sample.
Sources Handbook of Mineralogy
Limits of this research
- Research status: No authoritative source specific to this material was found; findings come from the parent material or are marked as gaps
- Chrome chalcedony's base is chalcedony (quartz), not an independent mineral species; no authoritative source for the specific definition of 'mtorolite' has been found, flagged as a gap.
- Chromium-colour evidence comes from GIA testing of an Aquaprase sample (green chalcedony with chromium and nickel), not a source dedicated to mtorolite.
- Green alone does not prove chromium colouring; testing is required. Not a judgement of origin, treatment or value.
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
- Chrome Chalcedony
CIBJO Gemmological Laboratories Book 2024 §7.2.1.51 “Chrome chalcedony (Mtorolite)” · IMA Mineral List 2026-07 “Quartz”
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
Chrome Chalcedony's material identity has open questions that are not fully settled; this site lists it as "Chrome Chalcedony" pending further verification.
Evidence
- CIBJO · 7.2.1.51
What this means for you
Before buying, check the recommended listing name "Chrome Chalcedony" 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
Care and wear
No care facts are recorded for this entry itself. Its parent material has care records: see Chalcedony.
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
Besides Chrome Chalcedony, the name register records "Mtorolite", for which no restriction on use as a name is recorded.
Names in four languagesThe names of Chrome Chalcedony are given in Simplified Chinese, Traditional Chinese, English (Chrome Chalcedony) and Japanese (a transliteration, pending check). Standard and listing namesThe suggested listing name is Chrome Chalcedony. This name itself is not listed in the standard, and its GB/T naming counterpart is chalcedony (GB/T 16552—2017 Table A.2 “Chalcedony (Agate/Jasper)”). Japanese namesThe Japanese GSJ formal name is given as the same transliteration (pending check); the GSJ wording has not yet been checked, and the name listed is the entry's own Japanese name. Trade and mineralogical namesThe trade name or synonym is Mtorolite, with no restriction on its use as a name recorded. The mineralogical name is given as Chrome chalcedony (mtorolite). Institution usageAmong authority wordings, CIBJO lists Chrome chalcedony (Mtorolite); the FTC source text has no wording for this name (checked); the wording of GIA and Gem-A has not been checked. Where a body has no recorded or checked wording, Chrome Chalcedony is the entry's own English name and does not represent that body's 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) | ||||
| MtoroliteEnglish | synonym | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- クロム・カルセドニー（待核） (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)
- 玉髓 (GB/T 16552—2017 Table A.2, row “Chalcedony(Agate/Jasper)”)
- Mineralogical name
- Chrome chalcedony (mtorolite): green chalcedony (quartz), colour due to chromium
- Trade names and synonyms
- Mtorolite (synonym)
Four-language names
- 简体中文
- 铬玉髓
- 繁體中文
- 鉻玉髓
- English
- Chrome Chalcedony
- 日本語
- クロム・カルセドニー（待核）
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
The composition (phase) of Chrome Chalcedony is quartz, as recorded in the CIBJO Gemmological Laboratories Book (2024). The body colour is green, registered for the untreated state; this site's qualification notes that other entries in Chapter 7 of the CIBJO Gemmological Laboratories Book also mention green or greenish colours, such as aventurine, diopside and emerald. Mohs hardness, density and refractive index are taken for chalcedony (including agate and jasper) as a whole class, not measured on Chrome Chalcedony separately: Mohs hardness 5–7, density 2.5–2.77 g/cm³ and refractive index 1.535–1.539, from GB/T 16553—2017; the refractive index clause has further sub-grades, and this site registers the overall value. Chemical composition, fluorescence, UV-visible spectrum, infrared spectrum and magnification are given for chalcedony as a whole class in the material facts of the Chalcedony entry and are not repeated for Chrome Chalcedony.
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 Chrome Chalcedony 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 Chrome Chalcedony (how to read class-level values).
Definition
Chrome Chalcedony — composition (phase): quartz
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
Durability
Chrome Chalcedony — 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
Physical properties
Chrome Chalcedony — 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
Chrome Chalcedony — 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
Chrome Chalcedony — body colour: Green.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Aventurine Quartz, Diopside, Emerald and other entries also name green or a greenish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- 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
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.
- 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 (Chrome Chalcedony) 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)
- Chrome Chalcedony
- Chrysocolla Chalcedony
- 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 |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Chrome Chalcedony 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.