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
Madeira Citrine
A trade variety name for deep orange-red to reddish-brown citrine, mostly produced by heating amethyst; “Madeira” does not indicate origin. 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 Madeira Citrine 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 Madeira CitrineHow far lab testing can go
- Treatments and enhancements of Madeira CitrineThe enhancements and treatments the GB/T and JJA/AGL tables list
- Hardness, density and refractive index of Madeira CitrineEach value with its source and check date
- Madeira Citrine 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 Madeira CitrineThe 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
Madeira citrine is a trade/colour name for citrine with a deep orange-red to reddish-brown tone. Citrine itself is the transparent pale-yellow to brownish-orange variety of quartz and is rare in nature; natural citrine can form by the natural conversion of amethyst under certain geologic conditions (more commonly to citrine, more rarely to green quartz) — the iron impurity in quartz forms a purple colour centre under low-grade radiation, and heat destabilises that centre to produce the yellow/orange colour. Because natural citrine is rare, most citrine on the market is the result of heat treatment (heating amethyst from undesirable pale violet to yellow). Note: the name "Madeira" does not appear in the authoritative sources consulted here (GIA Gem Encyclopedia, CIBJO Gemstone Book).
Scope: Applies to explaining the origin and naming boundary of Madeira citrine as a trade colour name for citrine (the yellow variety of quartz); the name itself has no authoritative definition in the cited sources (flagged as a grade C gap).
Sources G&G Spring 1982
Where it forms
Geologic settings of quartz growth/heating — natural citrine is rare.
Sources G&G Spring 1982
Natural citrine may form by conversion of amethyst under certain geologic conditions (mechanism after GIA's 1982 green-quartz study).
Sources G&G Spring 1982
How it forms, step by step
Quartz crystallizes from silica-bearing solutions with iron impurity present.
Sources GIA Citrine Description · CIBJO Gemstone Book 2022 · G&G Spring 1982
The iron impurity forms a purple colour centre (amethyst) under low-grade radiation.
Sources GIA Citrine Description · CIBJO Gemstone Book 2022 · G&G Spring 1982
Heating destabilises the purple centre to give the yellow/orange of citrine; most market citrine is produced this way.
Sources GIA Citrine Description · CIBJO Gemstone Book 2022 · G&G Spring 1982
Link to appearance
At its finest, citrine is a saturated yellow through reddish orange carrying no brownish tint; the label Madeira citrine marks a deeper orange-red to reddish-brown stone (that deeper shade is a trade descriptor — see the naming gap noted in this entry).
Sources GIA Citrine Description
Timescale
The sources state no absolute geological timescale for natural citrine formation.
Sources G&G Spring 1982
Related base materials
- Citrine (yellow quartz): Madeira citrine is a trade variety name for citrine (the yellow variety of quartz) tending towards deep orange-red to reddish brown
Supporting findings
Natural citrine can form by the natural conversion of amethyst under certain geologic conditions (more commonly to citrine, more rarely to green quartz).
Evidence grade AScope: A general statement of colour conversion in quartz; not verified for any particular "Madeira" locality.
Sources G&G Spring 1982
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
South America
- BrazilRefers to amethyst heated to citrine; the source does not discuss the Madeira grade separately.
Sources GIA Birthstones · Gems & Gemology Winter 2000
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
Citrine of the best quality is a saturated yellow through reddish orange, free from brownish tints.
Evidence grade BScope: A top-colour description; the deeper "Madeira" tone is a trade descriptor.
Sources GIA Citrine Description
Other research findings
Madeira citrine belongs to the citrine family — citrine being the clear quartz ranging from pale yellow to brownish orange. The name Madeira is a trade/colour label for a deeper orange-red to reddish-brown shade, not an independent mineral species.
Evidence grade BScope: Naming and variety classification; "Madeira" is a trade colour descriptor.
Sources GIA Citrine Description · CIBJO Gemstone Book 2022
The name "Madeira citrine" does not appear in the authoritative sources consulted (the GIA Gem Encyclopedia and the CIBJO Gemstone Book); it therefore has no authoritative mineralogical definition and does not constitute an identifiable material type.
Evidence grade CScope: Based only on the cited authoritative sources; where they are silent the gap is stated, not filled from commercial sites.
Sources GIA Citrine Description · CIBJO Gemstone Book 2022
Natural citrine is uncommon; it is the clear quartz whose hue spans pale yellow to brownish orange.
Evidence grade BScope: Describes citrine's composition/variety; not a specific locality.
Sources GIA Citrine Description
Because natural citrine is rare, most citrine on the market results from heat treatment — heating (some) amethyst from undesirable pale violet to an attractive yellow; CIBJO records citrine as "Heated (almost always)".
Evidence grade AScope: The typical market situation; not all citrine is necessarily treated.
Sources GIA Citrine Description · CIBJO Gemstone Book 2022
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
- "Madeira citrine" is not defined in the authoritative sources consulted, so what is said about the name rests on evidence level C only; the gap has not been filled with material from commercial gem shops or content farms.
- The natural-formation finding above is drawn from GIA's 1982 general account of colour conversion in quartz, not a study specific to any "Madeira" locality.
- No absolute geological timescale for natural citrine formation is given by the sources.
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
- Madeira Citrine
16 CFR Part 23 §23.24, §23.26(a)
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated (via parent material), Irradiated (via parent material), Filled / Fracture-filled (via parent material), Dyed (via parent material), Coated (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
"Madeira Citrine" is a market name rather than a mineral species name; before using it, verify: Trade name rather than a mineralogical species name.
Evidence
What this means for you
Before buying, check the recommended listing name "Madeira Citrine" 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
- Madeira Citrine
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 | — | — |
| Irradiation | — | — | Optimization | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Dyeing | — | — | Treatment | — | — |
| Coating | — | — | Treatment | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Rock Crystal)
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
Chinese standard nameUnder GB/T 16552—2017, the naming counterpart for Madeira Citrine is Citrine, but the name Madeira Citrine is not listed in the standard. Names in four languagesThe four-language names are given in Simplified Chinese, Traditional Chinese, English (Madeira Citrine) and Japanese (a transliteration); the entry's own Japanese name is the same transliteration, and the Japanese GSJ wording for it is not yet verified by this site. Recommended listing nameThe suggested listing name is deep-coloured citrine (Madeira Citrine). Institution usageIn the wording records of GIA, FTC, CIBJO and Gem-A, the FTC and CIBJO source texts have no wording for the name Madeira Citrine (checked); the wordings of GIA and Gem-A have not yet been checked. Bodies without a recorded wording show the English name Madeira Citrine, which does not represent their position. Trade and mineralogical namesThe mineralogical name refers to a trade variety name for deep orange-red to reddish-brown citrine. The identity tier of Madeira Citrine is trade name: colour or appearance variety.
- GSJ (Japan) formal name
- マデイラシトリン (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)
- 黄晶 (GB/T 16552—2017 §5.1.2.1 b))
- Mineralogical name
- Deep orange-red to reddish-brown citrine trade variety
Four-language names
- 简体中文
- 马德拉黄晶
- 繁體中文
- 馬德拉黃晶
- English
- Madeira Citrine
- 日本語
- マデイラシトリン
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
For the optimizations and treatments listed by standards, Madeira Citrine follows the Rock Crystal row of GB/T 16552—2017 Annex B, Table B.1: heating is listed as optimization, irradiation as optimization, filling is classed by the standard's grades, dyeing is listed as treatment and coating as treatment. The notes to Table B.1 and the definitions of the filling grades are on the Gem treatments page, and the full row with the effect column is on the Rock Crystal entry.
GB/T 16552-2017, Annex B, Table B.1
Under the “Rock Crystal” row of Table B.1: Heating Optimization; Irradiation Optimization; Filling Graded — see §5.4.1, Table 1; Dyeing Treatment; Coating Treatment. The full row, with the effect column, is on the Rock Crystal 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 Madeira Citrine are taken from the GB/T 16553—2017 clauses for rock crystal (the whole class), not measured separately. For rock crystal (the whole class), the structure is crystalline and trigonal; Mohs hardness is 7 and there is no cleavage; density is 2.64–2.69 g/cm³, derived from the clause value of 2.66 with a tolerance (+0.03/−0.02). For rock crystal (the whole class), the optic character is anisotropic, uniaxial positive; refractive index is 1.544–1.553 and birefringence 0.009; pleochroism is weak and varies with colour, untreated; the lustre is vitreous, untreated; and the cat's-eye effect and asterism can be seen, the stars being six-rayed and occurring mostly in rose quartz.
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 rock crystal (the whole class), so they are not repeated on the Madeira Citrine page; see the material facts on the Rock Crystal entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Madeira Citrine (how to read class-level values).
Structure
Madeira Citrine — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — structure (crystal system): trigonal
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — structure (crystal habit): hexagonal prisms with prominent horizontal striations on the prism faces
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Madeira Citrine — Mohs hardness: 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
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Madeira Citrine — density: 2.64–2.69 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
- Qualification
The clause we cite gives 2.66, with a stated tolerance of +0.03 / -0.02. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Madeira Citrine — optic character: anisotropic material, uniaxial, with positive optic character; a “Bull's eye” interference figure may be present, and Brazil-law twinning is common in amethyst.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — refractive index: 1.544–1.553
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — birefringence: 0.009
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — pleochroism: weak; it depends on the body colour.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Madeira Citrine — optical effect (asterism): seen; a six-rayed star, common in rose quartz.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- chatoyancy, asterism
Quality factors
Madeira Citrine — quality factor (lustre): vitreous
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- rock crystal (the whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (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): 1.548 / 2.67; Closest values: 1Agate 1.537 / 2.63, 2Shoushan Stone 1.56 / 2.7, 3Changhua Stone 1.56 / 2.6, 4Bamboo Coral 1.57 / 2.65, 5Synthetic Beryl 1.57 / 2.69
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 Madeira Citrine under “Quartz” (§6.1.65): see identification on the Quartz entry; the required tests are listed on the CIBJO laboratory protocol table for Quartz.
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
- 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.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia.
- Gem-A – The Gemmological Association of Great Britain (United Kingdom).
- eCFR (United States). 16 CFR § 23.24 — Disclosure of treatments to gemstones. In: 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 (Madeira Citrine) 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), Irradiated (via parent material), Filled / Fracture-filled (via parent material), Dyed (via parent material), Coated (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Madeira Citrine 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.