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Opal: History, Precious opal & Local atomic structure

Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may…

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Opal topic overview

The analysis highlights History, Precious opal and Local atomic structure as prominent areas in the source structure around Opal.

Related topics
98
Source areas
11
Connected nodes
156
Extracted relationships
279
Concept neighborhoods
29
Bridge connections
156

What this topic covers Research coverage

Source areas are shown by the number of related topics found in each part of the analysis. Use smaller areas too: they can reveal specialized angles and content gaps.

Overview · 17 topics
Local atomic structure · 15 topics
Precious opal · 15 topics
Examples · 12 topics
Common opal · 11 topics
Historical superstitions · 8 topics
Etymology · 7 topics
Synthetic opal · 5 topics
Varieties of common opal · 5 topics
History · 2 topics
Fossil opal · 1 topics

Smaller areas are not necessarily less important. They contain fewer connections in this analysis and can be useful for finding specialized angles or coverage gaps.

Key facts & relationships

High-confidence facts extracted from structured source data. Use them as anchors for further research.

Absorption spectra
green stones: 660 nm, 470 nm cutoff
Birefringence
none
Category
Mineraloid
Cleavage
None
Color
Colorless, white, yellow, red, orange, green, brown, black, blue, pink
Crystal habit
Irregular veins, in masses, in nodules

Explore all related topics Closing gaps

Browse the complete topic structure, not only the most central items. Less prominent entities and concepts can reveal missing angles, specialized context and useful research gaps. Each item opens a new analysis centered on that subject.

Overview

Precious opal

Common opal

Varieties of common opal

History

Sources

Fossil opal

Synthetic opal

Local atomic structure

Etymology

Historical superstitions

Examples

Advanced semantic analysis

Deeper signals for content research, entity SEO and topical coverage. The plain-language headings explain what each technical view is useful for.

How Opal connects Entity context

The extracted context around Opal shows recurring relationship patterns in the source. For example, Opal → Andamooka, Australia, Beauharnais, Beverly, Bug, Coober PedyThe Andamooka Opal, Earth, Fire, Flame Queen OpalOpal, France, Grand Central Terminal, Guinness Book, Joséphine, Napoleon, New York City, Queen Elizabeth II, Queen's OpalThe Addyman, RecordsThe Rainbow Virgin, Roebling Opal, Smithsonian InstitutionThe Galaxy Opal Another extracted example is Opal → December, Farlang, February, Fields, Fossils, Georg Agricola, Hist, ICA's Opal Page, International Colored Stone AssociationOpal, Isaac Newton, Map, Mineralogy DatabaseOpalworld Archived, October, Opal Mineral, References Archived, South Australian Museum Archived, Theophrastus, Wayback Machine Accessed, Wayback Machine Australian Opal, Wayback Machine Localities. Use these groups to spot repeated connection types before inspecting the individual relationships.

Opal

Top relations

related to Examples · 26
Opal → Andamooka, Australia, Beauharnais, Beverly, Bug, Coober PedyThe Andamooka Opal, Earth, Fire, Flame Queen OpalOpal, France, Grand Central Terminal, Guinness Book, Joséphine, Napoleon, New York City, Queen Elizabeth II, Queen's OpalThe Addyman, RecordsThe Rainbow Virgin, Roebling Opal, Smithsonian InstitutionThe Galaxy Opal
related to External links · 20
Opal → December, Farlang, February, Fields, Fossils, Georg Agricola, Hist, ICA's Opal Page, International Colored Stone AssociationOpal, Isaac Newton, Map, Mineralogy DatabaseOpalworld Archived, October, Opal Mineral, References Archived, South Australian Museum Archived, Theophrastus, Wayback Machine Accessed, Wayback Machine Australian Opal, Wayback Machine Localities
related to Historical superstitions · 18
Opal → April, Arnheim, As, Baroness, Due, Europe, Even, Following, Geierstein, In, In Scott's, It, Middle Ages, Russian, Scott's, Sir Walter Scott's Anne, When, Within
related to Other locations · 18
Opal → Another, Brazil, Canada, Czech Republic, Erandique, Guatemala, Honduras, Hungary, Idaho, Indonesia, Nicaragua, Other, Pedro II, Piauí, Slovakia, Spencer, Turkey, United States
related to Virgin Valley, Nevada · 18
Opal → Black Peacock, Bonanza, Humboldt County, Miocene-age, Most, Nevada, Opal Queen, Opals, Rainbow Ridge, Rainbow Ridge Mine, Roebling, Royal Peacock, Smithsonian Institution, Some, The, The Virgin Valley, Virgin Valley, WRT Stonetree/Black Beauty
related to Ethiopia · 17
Opal → Australia, Brazil, Ethiopia, Ethiopia's Wollo Province, Ethiopian, In, Menz Gishe District, North Shewa Province, Shewa Province, The, The Wollo Province, These, This Shewa Province, Wegeltena, Wello, Welo, Wollo Province
related to Mexico · 16
Opal → Although, Another, Cantera, Colón, During, Ezequiel Montes, Fire, In, Mexican, Mexico, Querétaro, Tequisquiapan, The, This, Today's, US
related to Sources · 14
Opal → Australia, Australian, Because, Ethiopia, Ethiopian, In, Laurs, Mesfin, South Australia, The, United States Geological Survey, USGS, Wegeltena, Yet
related to Varieties of common opal · 14
Opal → Blue, Girasol, However, Idaho, It, Madagascar, Mexico, Nevada, Oregon, Owyhee, Peru, Peruvian, The, Virgin Valley
related to Etymology · 11
Opal → As, Elder, Latin, Opalia, Ops, Pliny, Roman, Sanskrit, Saturn, Saturnalia, The

Important terminology

Use these terms to understand the vocabulary surrounding the topic, not as a checklist for keyword stuffing.

Important terminology

opals precious also silica color black water may common found australia light form play fire amorphous structure often white around

Opal relationships Subject–Predicate–Object triples

TTTA extracted 279 structured relationships around Opal. Examples in this analysis include Opal → Absorption spectra → green stones: 660 nm, 470 nm cutoff and Opal → Birefringence → none. The table shows each extracted connection, where it came from and its confidence.

SubjectPredicateObjectConfidenceSrc
OpalAbsorption spectragreen stones: 660 nm, 470 nm cutoff1.00infobox
OpalBirefringencenone1.00infobox
OpalCategoryMineraloid1.00infobox
OpalCleavageNone1.00infobox
OpalColorColorless, white, yellow, red, orange, green, brown, black, blue, pink1.00infobox
OpalCrystal habitIrregular veins, in masses, in nodules1.00infobox
OpalCrystal systemAmorphous1.00infobox
OpalDensity2.09 g/cm31.00infobox
OpalDiagnostic featuresdarkening upon heating1.00infobox
OpalDiaphaneityopaque, translucent, transparent1.00infobox
OpalFormulaHydrated silica. SiO2·nH2O1.00infobox
OpalFractureConchoidal to uneven1.00infobox
OpalIMA symbolOpl1.00infobox
OpalLusterSubvitreous to waxy1.00infobox
OpalMohs scale hardness5.5–61.00infobox
OpalOptical propertiesSingle refractive, often anomalous double refractive due to strain1.00infobox
OpalPleochroismNone1.00infobox
OpalPolish lusterVitreous to resinous1.00infobox
OpalRefractive index1.450+0.020 −0.080 Mexican opal may read as low as 1.37, but typically reads 1.42–1.431.00infobox
OpalSolubilityhot salt water, bases, methanol, humic acid, hydrofluoric acid1.00infobox
OpalSpecific gravity2.15+0.08 −0.901.00infobox
OpalStreakWhite1.00infobox
OpalUltraviolet fluorescenceblack or white body color: inert to white to moderate light blue, green, or yellow in long and short wave, may also phosphoresce, common opal: inert to strong green or yellowish…1.00infobox
Opalcausesit to diffract light0.90text
Opalis ahydrated amorphous form of silica0.90text
Opalis atype of hyalite opal that exhibits a bluish glow or sheen that follows the light source around0.90text
Opalis anational gemstone of Australia0.90text
Opalis aofficial gemstone of Nevada0.90text
Opalis atransparent to translucent opal with warm body colors of yellow to orange to red0.90text

Related concept clusters Concept neighborhoods

The concept neighborhoods around Opal bring nearby vocabulary together. In this analysis, examples include Precious, Black and Also. Use the clusters to find adjacent concepts and terminology that may deserve separate research.

  • Opal
    • Precious
    • Black
    • Also
    • Color
    • Australia
    • Common
    • Found
    • Water
    • Fire
    • May
    • Light
    • Silica
  • opal
    • Precious
    • Black
    • Also
    • Color
    • Australia
    • Common
    • Found
    • Water
    • Fire
    • May
    • Light
    • Silica
  • hydrated
    • Mineraloid
    • References
    • Amorphous
    • Silica
    • Structure
    • Common
    • May
    • Water
    • Matrix
    • Opaque
    • Optical
    • Virgin
  • amorphous
    • Silica
    • Hydrated
    • Mineraloid
    • Structure
    • May
    • Water
    • Opals
    • Commonly
    • Opaque
    • Optical
    • References
    • Considered
  • silica
    • Structure
    • Spheres
    • Mineraloid
    • Light
    • First
    • Also
    • Water
    • Optical
    • References
    • Virgin
    • Common
    • Often
  • south australia
    • South
    • Also
    • Black
    • Matrix
    • Virgin
    • Opal
    • Often
    • Light
    • Found
    • Silica
    • Stone
    • Hydrated
  • mintabie opal field
    • Precious
    • Black
    • Also
    • Color
    • Australia
    • Common
    • Found
    • Water
    • Fire
    • May
    • Light
    • Silica
  • andamooka opal
    • Precious
    • Black
    • Also
    • Color
    • Australia
    • Common
    • Found
    • Water
    • Fire
    • May
    • Light
    • Silica

Connections between topic areas Semantic bridges

For Opal, one of the stronger structural bridges in this analysis connects Opal with Sources. Bridges highlight paths between different parts of the map and can reveal research angles that are easy to miss in a flat list.

Min side: 3
Opal — Sources · splits 110 ⟂ 47
Opal — Overview · splits 139 ⟂ 18
Opal — Precious opal · splits 141 ⟂ 16
Opal — Local atomic structure · splits 141 ⟂ 16
Opal — Examples · splits 144 ⟂ 13
Opal — Common opal · splits 145 ⟂ 12
Opal — Historical superstitions · splits 148 ⟂ 9
Opal — Etymology · splits 149 ⟂ 8
Opal — Varieties of common opal · splits 151 ⟂ 6
Opal — Synthetic opal · splits 151 ⟂ 6
Opal — History · splits 154 ⟂ 3

Map overview Semantic statistics

Opal

Nodes157
Edges156
Triples279
Avg. degree1.99
Density0.012739
Components1

Source & methodology

TTTA analyzes the structure around Opal to surface related topics, entities, relationships, concept neighborhoods and bridge connections. Use the map to explore areas such as History, Precious opal & Local atomic structure, including less central topics that may reveal useful research gaps. Automatically extracted connections are research leads rather than rewritten encyclopedia content.

Source: Wikipedia — Opal · EN edition · Analysis: TopicsToTalkAbout

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