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
Rock Crystal
A basic name listed in GB/T 16552-2017 Table A.1. It originally means colorless transparent quartz and is also used as the parent name for the various quartz varieties. 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 Rock Crystal 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 Rock CrystalIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Rock Crystal5 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing Rock CrystalDurability indicators and wearing advice
- Hardness, density and refractive index of Rock CrystalEach value with its source and check date
- Rock Crystal 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 Rock CrystalWhere the name comes from; how people have used it, with museum objects
- Listing and disclosing Rock CrystalThe 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
Rock crystal is the gemological use of colourless, transparent quartz; its parent material is the SiO2 mineral quartz. Quartz is one of the most widely distributed minerals, crystallizing in hydrothermal veins, epithermal to alpine veins, granites and granite pegmatites, as well as in sandstones, quartzites and carbonate rocks. The colourless appearance of rock crystal reflects the absence of colour-causing trace impurities or colour centres in the lattice rather than a distinct substance: quartz is SiO2 with traces of other elements, and its colours arise from chemical or particulate inclusions. In granitic vugs and hydrothermal veins, colourless transparent crystals form by slow deposition from silica-bearing solutions.
Scope: Applies to the material formation and identity definition of colourless transparent quartz (rock crystal); the specific GB/T classification clauses cannot be verified, and this record contains no standard clause content.
Sources Handbook of Mineralogy · G&G Spring 1982
Where it forms
Hydrothermal veins, epithermal to alpine veins; granitic and pegmatite vugs
Sources Handbook of Mineralogy · G&G Spring 1982
Also a residual mineral in soils and sediments
Sources Handbook of Mineralogy · G&G Spring 1982
How it forms, step by step
Silica-bearing fluids migrate through fractures, vugs, or pores in the rock.
Sources Handbook of Mineralogy · G&G Spring 1982
Silica slowly precipitates, accumulates, and crystallizes as quartz from migrating solutions.
Sources Handbook of Mineralogy · G&G Spring 1982
Where the lattice lacks colouring impurities or colour centres, the transparent quartz that crystallizes is colourless rock crystal.
Sources Handbook of Mineralogy · G&G Spring 1982
Link to appearance
Colourless and transparent with vitreous lustre; the absence of colour reflects a lattice without colouring impurities or colour centres, not a different substance.
Sources Handbook of Mineralogy
Timescale
The sources state no absolute age or duration for rock crystal crystallization.
Sources Handbook of Mineralogy · G&G Spring 1982
Related base materials
- Quartz (SiO2): parent-mineral | Rock crystal is colourless, transparent quartz; its parent material is the mineral quartz, SiO2
Supporting findings
Quartz occurs chiefly in hydrothermal veins (epithermal to alpine), granites and granite pegmatites, and also in sandstones, quartzites and carbonate rocks.
Evidence grade BScope: Summarizes quartz occurrence; not every occurrence yields gem-grade material.
Sources Handbook of Mineralogy
In rock cavities and fractures, quartz forms by slow deposition and accumulation from migrating silica-bearing solutions.
Evidence grade AScope: Describes precipitation from silica-bearing solutions; not all quartz genesis included.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Tamboholehehibe and elsewhere, Madagascar
Sources Handbook of Mineralogy
Asia
- Sakangyi, Katha, Sagaing, Myanmar
Sources Handbook of Mineralogy
- Yamanashi Prefecture, Japan
Sources Handbook of Mineralogy
Europe
- Swiss Alps, Switzerland
Sources Handbook of Mineralogy
- Austrian Alps, Austria
Sources Handbook of Mineralogy
- Carrara, Tuscany, Italy
Sources Handbook of Mineralogy
- Bourg d'Oisans, Isère, France
Sources Handbook of Mineralogy
- Murzinka and Dodo mine, Ural Mountains, Russia
Sources Handbook of Mineralogy
North America
- Thunder Bay, Ontario, Canada
Sources Handbook of Mineralogy
- Mount Ida to Hot Springs, Ouachita Mountains, Arkansas, United States
Sources Handbook of Mineralogy
- Middleville, Herkimer County, New York, United States
Sources Handbook of Mineralogy
- Alexander and Lincoln counties, North Carolina, United States
Sources Handbook of Mineralogy
- Pala and Mesa Grande districts, San Diego County, California, United States
Sources Handbook of Mineralogy
- El Capitan Mountains, Lincoln County, New Mexico, United States
Sources Handbook of Mineralogy
- Crystal Park and Little Pipestone Creek, Montana, United States
Sources Handbook of Mineralogy
- Pikes Peak area, Colorado, United States
Sources Handbook of Mineralogy
- Veracruz and Guerrero, Mexico
Sources Handbook of Mineralogy
South America
- Rio Grande do Sul, Brazil
Sources Handbook of Mineralogy
- Minas Gerais, Brazil
Sources Handbook of Mineralogy
- Goiás, BrazilGoiás is broken in the HoM text layer
Sources Handbook of Mineralogy
- Bahia, Brazil
Sources Handbook of Mineralogy
- Artigas area, Uruguay
Sources Handbook of Mineralogy
Seas and coasts
- WorldwideHoM: extraordinarily common
Sources Handbook of Mineralogy
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
Quartz colourlessness reflects the absence of colouring impurities or colour centres; its colours arise mainly from chemical or particulate inclusions.
Evidence grade BScope: Explains the relation between colour and impurities/inclusions; not a specimen identification.
Sources Handbook of Mineralogy
Where the name comes from
The name rock crystal is not given an etymology by the cited sources; the etymologies belong to its parent minerals: quartz is of obscure origin in the Middle Ages, first applied to gangue in Saxony, Germany. These etymologies belong to those parent minerals, not to the trade name.
Evidence grade BScope: The etymology explains the origin of a name only; it does not attest composition, locality, naturalness or treatment, and here belongs to the parent mineral rather than to the trade name itself.
Sources Handbook of Mineralogy
Human use and museum objects
As colourless quartz, rock crystal has been made into beads at least since ca. the late 8th millennium BCE, e.g. a Neolithic bead from Syria (The Met, 1985.356.72); Minoan, Roman and Unified Silla collections further document rock crystal beads, bottles and inlaid ornaments (The Met, 26.31.403, 74.51.3600, 74.51.3619; Cleveland Museum of Art, 1945.380).
Evidence grade AScope: Cites museum objects as instances of rock crystal beadwork; evidence pertains to the quartz parent material, with no deposit or modern-sample determination.
Sources The Met 1985.356.72 · Cleveland Museum of Art 1945.380
Museum objects show that rock crystal, the colourless transparent variety of quartz, was worked into beads and ornaments since prehistory. The earliest documented piece is a Neolithic rock crystal bead from Syria (The Met, 1985.356.72, ca. late 8th millennium BCE); Minoan Crete also yields striated and shield-shaped rock crystal beads (The Met, 26.31.403, 26.31.404, ca. 2200–1450 BCE). Later examples include a Cypriot or Phoenician rock crystal bottle (The Met, 74.51.3600, ca. 5th–2nd century BCE), a Roman gold earring with a rock crystal bead (The Met, 74.51.3619, 1st–2nd century CE) and a Unified Silla necklace with rock crystal beads (Cleveland Museum of Art, 1945.380, 700s). Per museum records these are catalogued as the rock-crystal variety of quartz; the evidence belongs to the quartz parent material and is not exclusive to the name 'rock crystal'.
Sources The Met 1985.356.72 · Cleveland Museum of Art 1945.380
Scope: Museum objects attest only to the existence and date of the individual documented pieces; they do not evidence widespread ancient use of the material, nor the origin, naturalness or treatment of any modern specimen. Cultural attribution follows the museum's record and is not extrapolated.
Objects cited
- The Met 1985.356.72Rock crystal
- The Met 26.31.403Rock crystal
- The Met 26.31.404Rock Crystal
- The Met 74.51.3600Rock crystal
- The Met 74.51.3619Gold, Rock crystal
- Cleveland Museum of Art 1945.380jade, amethyst, gold, rock crystal
How it is identified
A rock crystal's colour and apparent clarity do not prove whether it is natural or synthetic, nor whether it was treated. Laboratory identification normally combines microscopic observation of twinning and colour zoning, chemical analysis such as EDXRF, infrared spectroscopy, and where needed a polariscope (conoscope) or refractometer to judge how a colour boundary lies relative to the optic axis. Interpretation needs specialist knowledge, so the conclusion should be issued by a qualified gem laboratory rather than the unaided eye.
Evidence grade AScope: Applies where natural and synthetic quartz must be distinguished; no self-administered criteria are given.
Sources G&G Summer 2014 · CIBJO Gemstone Book 2022
Other research findings
Rock crystal (colourless transparent quartz) is chiefly SiO2 with only traces of other elements.
Evidence grade BScope: States quartz composition only; no deposit or quality determination.
Sources Handbook of Mineralogy
According to the 1988 GIA article "Faceting Large Gemstones", the largest faceted quartz (rock crystal) egg then recorded was 7,000 ct, cut by John Sinkankas and held at the Smithsonian Institution, Washington DC. The same article's table lists a further smoky quartz record, but that table is incomplete in the text extraction (the leading digit of its weight is missing), so the figure is not quoted here. These records come from 1988 and may since have been superseded.
Evidence grade AScope: A record statement, superseded over time; the records date from 1988. Concerns a faceted quartz egg, not a rough-crystal record. Figures from the incomplete table extraction are not quoted.
Sources G&G Spring 1988
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The full texts of GB/T 16552-2017 and GB/T 34098-2017 are not obtainable; no clause text was verified and no classification table was invented.
- The sources give no absolute temperature, pressure or age for quartz crystallization.
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
- Rock Crystal (colourless transparent quartz)
GB/T 16552—2017 Table A.1 “Rock Crystal” · IMA Mineral List 2026-07 “Quartz”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated, Irradiated, Filled / Fracture-filled, Dyed, Coated
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
Rock Crystal is Colourless transparent quartz; GB/T parent term for quartz gem materials; use "Rock Crystal (colourless transparent quartz)" for listings, and disclose any known treatments.
Evidence
- GB/T · Table A.1, row 水晶 (Rock Crystal)
What this means for you
Before buying, check the recommended listing name "Rock Crystal (colourless transparent quartz)" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
Known uncertainty
- Last reviewed
- 2026-09-01
Care and wear
No care facts are recorded for this entry itself. Its parent material has care records: see Quartz.
Durability and wearing
Toughness
Brittle, tough when massive
Daily wear
Rock crystal is colourless transparent quartz, Mohs 7 and fairly durable for daily wear; however it is brittle with conchoidal fracture, can crack on impact, and will abrade softer stones — the main risks are knocking and surface abrasion.
Care
Clean with warm water, mild soap and a soft brush; quartz generally tolerates ultrasonic/steam cleaning, but fractured or treated pieces should be handled cautiously; avoid thermal shock and heavy impact.
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 general material properties and does not constitute a durability or safety warranty for any specific finished product; the durability of treated (filling/dyeing/coating) or assembled pieces must be assessed separately.
Treatments and identification leads
Registered treatmentsThe registered treatments for Rock Crystal are heating, irradiation, filling, coating and dyeing. Heating, filling and coating have the status treated, irradiation the status irradiated or dyed, and dyeing the status colour-treated. Values not givenStability and prevalence are all recorded as “—”, meaning the cited source gives no value, not “none”. Stability and frequencyHeating can lighten dark amethyst, remove brownish tones from quartz, or turn amethyst into citrine or green quartz, and heated quartz-family gems have stable colour and are hard to detect; irradiation can turn colourless quartz into smoky quartz and deepen the colour of rose quartz, both hard to detect; filling, coating and dyeing each have their own identification leads as well, with GB/T 16553—2017 as the source.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| heatingStatus: treated | — | — | Optimization | — | See identification leads |
| irradiationStatus: irradiated or dyed | — | — | Optimization | — | See identification leads |
| fillingStatus: treated | — | — | Graded — see §5.4.1, Table 1 | — | See identification leads |
| coatingStatus: treated | — | — | Treatment | — | See identification leads |
| dyeingStatus: colour treated | — | — | Treatment | — | See identification leads |
Where each treatment acts (schematics): Heated / Heat-treated · Irradiated · Filled / Fracture-filled · Coated · Dyed
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017; GB/T 16552—2017 Table B.1
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
Standard and listing namesThe Chinese formal name of Rock Crystal in GB/T 16552—2017 Table A.1 corresponds to Rock Crystal; the suggested listing name is Rock Crystal (colourless transparent quartz). Trade and mineralogical namesThe mineralogical name is colourless transparent quartz, which GB/T uses as the parent name for quartz gem materials. Names in four languagesThe four-language names are the Simplified and Traditional Chinese names, English Rock Crystal and the Japanese names. The GSJ (Japan) formal name is written in kanji, with a note on Japan-law twinning. Institution usageFor authority wording, GIA records Rock Crystal (colorless quartz), FTC records Quartz (colorless), and CIBJO records Rock Crystal, with the qualifier quartz variety stripped from the headline name; Gem-A is unchecked, and Rock Crystal is the entry's own English name, which does not represent Gem-A's position.
- GSJ (Japan) formal name
- 水晶（日本式双晶）
- Chinese formal name
- 水晶 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Colourless transparent quartz; GB/T parent term for quartz gem materials
Four-language names
- 简体中文
- 水晶
- 繁體中文
- 水晶
- English
- Rock Crystal
- 日本語
- 水晶／ロッククリスタル
Qualifiers stripped from the headline name
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 Rock Crystal, the Rock Crystal row of Table B.1 in Annex B of GB/T 16552—2017 lists heating, which improves or changes colour, in the category optimization; irradiation, which changes colour, in the category optimization; filling, which improves or changes durability and appearance, with its category given by grade; dyeing, which improves or changes colour, in the category treatment; and coating, which improves or changes lustre, colour and other aspects of appearance, in the category treatment. For what Table B.1 is and how the grades for filling are defined, see the Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Table B.1, row “Rock Crystal” (p.15):
This table scrolls sideways on narrow screens.
| Method | Effect | Category |
|---|---|---|
| Heating | Improves or changes colour | Optimization |
| Irradiation | Changes colour | Optimization |
| Filling | Improves or changes durability and appearance | Graded — see §5.4.1, Table 1 |
| Dyeing | Improves or changes colour | Treatment |
| Coating | Improves or changes lustre, colour and other aspects of appearance | Treatment |
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 composition (chemistry) of Rock Crystal is SiO2, which may contain elements such as Ti, Fe and Al, and the phase is quartz; it is crystalline and trigonal, with hexagonal prismatic crystals and distinct horizontal striations on the prism faces. Mohs hardness is 7, with no cleavage; this site notes that hardness alone is not enough to judge durability. Density is 2.64–2.69 g/cm³; the cited clause gives 2.66 with an allowed deviation of +0.03/−0.02, from which the limits are derived. The refractive index is 1.544–1.553 and birefringence 0.009; optically it is anisotropic, uniaxial and positive, possibly showing a bull's-eye interference figure, and Brazil-law twinning is common in amethyst. Among optical effects, a cat's-eye effect may be seen; a star effect may be seen, six-rayed, mostly in rose quartz; iridescence is also registered. When untreated, rock crystal shows weak pleochroism varying with colour, no fluorescence and a vitreous lustre.
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”.
Definition
Rock Crystal — composition (chemistry): SiO2, elements such as Ti,Fe and Al may be contained.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — composition (phase): quartz
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Rock Crystal — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — structure (crystal system): trigonal
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — 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
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Rock Crystal — 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
- General note
- hardness only, not durability
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Rock Crystal — density: 2.64–2.69 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- 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 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Rock Crystal — 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
Source & check 2026-09-22
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-22)
- Fact checked on
- 2026-09-22
Rock Crystal — refractive index: 1.544–1.553
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — birefringence: 0.009
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — transparency: transparent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Rock Crystal — pleochroism: weak; it depends on the body colour.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — fluorescence (overall): none
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — spectrum (UV-visible): non-characteristic
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — spectrum (infrared): diagnostic bands of rock crystal in the mid-IR
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — optical effect (iridescence): iridescent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Rock Crystal — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — optical effect (asterism): seen; a six-rayed star, common in rose quartz.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal — magnification: gas-liquid inclusions, three-phase inclusions, growth striations, color band, twin striations, mineral inclusions, for example acicular rutile and tourmaline, negative crystals.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Rock Crystal — body colour: colourless, or light to dark purple, light to dark yellow, light to dark brown, green to yellow-green, light to medium pink and similar colours.
By variety: amethyst is light to dark purple; citrine is light to dark yellow; smoky quartz is light to dark brown; green quartz is green to yellow-green; rose quartz is light to medium pink, lighter in tone; rutilated quartz is colourless, light yellow, light brown and similar, and may often be golden yellow or brownish red because of rutile, often greyish black because of tourmaline, or greyish green because of actinolite.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
The colours GB/T 16553—2017 lists for Synthetic Quartz overlap with this entry: colourless, purple and yellow; the standard notes that the cobalt blue listed for synthetic quartz has not been found in natural quartz.
- General note
- colour alone is not identity
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
Rock Crystal — body colour: Colourless.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Achroite, Crystal Opal, Goshenite and other entries also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
How the sources relate
- GB/T 16553—2017 and CIBJO Gemmological Laboratories Book 2024
The two entries cover different ranges.
In the CIBJO Gemmological Laboratories Book, rock crystal means colourless, transparent quartz only; the GB/T 16553—2017 rock crystal entry covers quartz of many colours, including amethyst, citrine, smoky quartz, green quartz, rose quartz and rutilated quartz, with colourless as one of them. They agree on colourless.
- CIBJO definitions
- chatoyancy, asterism
Quality factors
Rock Crystal — quality factor (lustre): vitreous
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
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 Rock Crystal 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
Rock Crystal that has undergone heating can be identified by the following features: a) heating dark amethyst can lighten the colour. b) heating can remove a brown tint in rock crystal. c) heating amethyst can turn it into citrine or green quartz. The colour of heated quartz stones is stable and the treatment is not easy to detect.
GB/T 16553—2017
- Treatment state
- treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- heating
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (heating) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal that has undergone irradiation can be identified by the following features: a) irradiating rock crystal can turn it into smoky quartz; hard to detect. b) irradiating rose quartz can deepen the colour; hard to detect.
GB/T 16553—2017
- Treatment state
- irradiated or dyed
- Does this standard apply
- can be followed as a reference only
- Treatment
- irradiation
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (irradiation) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal that has undergone filling can be identified by the following features: Under magnification the exposed part of the filler has a surface luster differing from that of the host stone, and the filled area may show a flash effect and gas bubbles; infrared spectra show characteristic absorption bands of the filler; luminescence imaging (such as a UV fluorescence viewer) shows how the filler is distributed.
GB/T 16553—2017
- Treatment state
- treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- filling
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (filling) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal that has undergone coating can be identified by the following features: Under magnification the surface luster is abnormal and the film can be seen peeling off in places; refractive index readings may be abnormal; infrared and Raman spectra show characteristic peaks of the film.
GB/T 16553—2017
- Treatment state
- treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- coating
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (coating) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Rock Crystal that has undergone dyeing can be identified by the following features: Under magnification the colour is unevenly distributed and mostly concentrated in fissures or in surface hollows; the dye may show a distinctive fluorescence under long- or short-wave UV.
GB/T 16553—2017
- Treatment state
- colour treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- dyeing
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (dyeing) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
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.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- Geological Survey of Japan, AIST (Japan). Museum mineral specimens, browse by classification.
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 (Rock Crystal) 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, Irradiated, Filled / Fracture-filled, Dyed, Coated | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Rock Crystal 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.