Opal
E60368
Opal is a precious gemstone renowned for its vibrant play-of-color and is especially associated with major deposits in Australia.
Observed surface forms (1)
| Surface form | Occurrences |
|---|---|
| Australian black opal | 1 |
Statements (50)
| Predicate | Object |
|---|---|
| instanceOf |
gemstone
ⓘ
mineraloid ⓘ |
| canExhibit | crazing ⓘ |
| containsComponent | water ⓘ |
| containsElement |
oxygen
ⓘ
silicon ⓘ |
| formsBy | precipitation from silica-rich solutions ⓘ |
| formsIn |
sedimentary rocks
ⓘ
volcanic rocks ⓘ |
| hasChemicalComposition | hydrated silica ⓘ |
| hasChemicalFormula | SiO2·nH2O ⓘ |
| hasCleavage | none ⓘ |
| hasColor |
black
ⓘ
blue ⓘ colorless ⓘ orange ⓘ red ⓘ white ⓘ |
| hasCrystalSystem | amorphous ⓘ |
| hasFracture | conchoidal ⓘ |
| hasLuster |
vitreous
ⓘ
waxy ⓘ |
| hasMajorDepositIn |
Australia
ⓘ
Brazil ⓘ Ethiopia ⓘ Mexico ⓘ United States of America ⓘ
surface form:
United States
|
| hasMohsHardness | 5.5–6.5 ⓘ |
| hasOpticalEffect |
opalescence
ⓘ
play-of-color ⓘ |
| hasRefractiveIndex | 1.37–1.52 ⓘ |
| hasSpecificGravity | 1.9–2.3 ⓘ |
| hasTypicalTransparency | transparent to opaque ⓘ |
| hasVariety |
black opal
ⓘ
boulder opal ⓘ common opal ⓘ crystal opal ⓘ fire opal ⓘ matrix opal ⓘ precious opal ⓘ white opal ⓘ |
| isAssociatedWithCountry | Australia ⓘ |
| isBirthstoneFor | October ⓘ |
| isNationalGemstoneOf | Australia ⓘ |
| isPrimarilyFoundIn | Australia ⓘ |
| isRenownedFor | vibrant play-of-color ⓘ |
| isSensitiveTo |
dehydration
ⓘ
sudden temperature changes ⓘ |
| isUsedFor |
jewelry
ⓘ
ornamental objects ⓘ |
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Australian black opal