Mindat Logo

Cristobalite

This page is currently not sponsored. Click here to sponsor this page.



Formula:
SiO
 
2
System:TetragonalColour:Colorless, white, also ...
Lustre:VitreousHardness:6 - 7
Name:Named after its locality (Cerro San Cristobal, Mexico)
Polymorph of:Coesite, Quartz, Stishovite, Tridymite


Post-volcanic, magmatic, and secondary. Common constituent of certain types of opal (opal-C and opal-CT) in marine sediments rich in biogenic silica.

May be intergrown with Tridymite.

Classification of Cristobalite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:4/D.01-30
Nickel-Strunz 10th (pending) edition ID:4.DA.15

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
A : With small cations: Silica family
Dana 8th edition ID:75.1.1.1

75 : TECTOSILICATES Si Tetrahedral Frameworks
1 : Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Hey's CIM Ref.:7.8.5

7 : Oxides and Hydroxides
8 : Oxides of Si
mindat.org URL:http://www.mindat.org/min-1155.html
Please feel free to link to this page.

Type Occurrence of Cristobalite

Type Locality:Cerro San Cristóbal, Mun. de Pachuca, Hidalgo, Mexico
Year of Discovery:1887

Occurrences of Cristobalite

Geological Setting:Individual crystals in vesicles and lithophysae. Common constituent of opal (opal-C and opal-CT) in sedimentary rocks and silicious sinter.

Physical Properties of Cristobalite

Lustre:Vitreous
Diaphaneity (Transparency):Transparent, Translucent
Colour:Colorless, white, also blue grey, brown, grey, yellow
Comment:Often white due to numerous cracks
Streak:White
Hardness (Mohs):6 - 7
Tenacity:Brittle
Density (measured):2.32 - 2.36 g/cm3
Density (calculated):2.33 g/cm3

Crystallography of Cristobalite

Crystal System:Tetragonal
Class (H-M):4 2 2 - Trapezohedral
Space Group:P41 21 2
Cell Parameters:a = 4.9709(1) Å, c = 6.9278(2) Å
Ratio:a:c = 1 : 1.394
Unit Cell Volume:V 171.18 ų (Calculated from Unit Cell)
Z:4
Morphology:Pseudo octahedral crystals, commonly dendritic, spherulites.
Twinning:On {111}
Crystal Atlas:
Image Loading
Click on an icon to view
Cristobalite no.1 - Goldschmidt (1913-1926)

About Crystal Atlas

The mindat.org Crystal Atlas allows you to view a selection of crystal drawings of real and idealised crystal forms for this mineral and, in certain cases, 3d rotating crystal objects. The 3d models and HTML5 code are kindly provided by www.smorf.nl.

Toggle
Edge Lines | Miller Indicies | Axes

Transparency
Opaque | Translucent | Transparent

View
Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation
X-Ray Powder Diffraction:
d-spacingIntensity
4.05 (100)
3.135 (11)
2.841 (13)
2.485 (20)
2.465 (5)
2.118 (5)
1.870 (7)
Comments:For synthetic material.

Optical Data of Cristobalite

Type:Uniaxial (-)
RI values: nω = 1.487 nε = 1.484
Maximum Birefringence:δ = 0.003

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate

Chemical Properties of Cristobalite

Formula:
SiO
 
2
Simplified for copy/paste:SiO2
Essential elements:O, Si
All elements listed in formula:O, Si
Common Impurities:Fe,Ca,Al,K,Na,Ti,Mn,Mg,P

Relationship of Cristobalite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
4.DA.05Quartz
SiO
 
2
4.DA.10Opal
SiO
 
2
· nH
 
2
O
4.DA.10Tridymite
SiO
 
2
4.DA.20Mogánite
SiO
 
2
4.DA.25Melanophlogite
46SiO
 
2
· 6(N
 
2
,CO
 
2
) · 2(CH
 
4
,N
 
2
)
4.DA.30Lechatelierite
SiO
 
2
4.DA.35Coesite
SiO
 
2
4.DA.40Stishovite
SiO
 
2
4.DA.45Keatite
SiO
 
2
4.DA.50Seifertite
SiO
 
2
Related Minerals - Hey's Index Grouping:

- +
7.8.1Quartz
SiO
 
2
7.8.2Coesite
SiO
 
2
7.8.3Tridymite
SiO
 
2
7.8.4Stishovite
SiO
 
2
7.8.6Lechatelierite
SiO
 
2
7.8.7Silhydrite
3SiO
 
2
· H
 
2
O
7.8.8Opal
SiO
 
2
· nH
 
2
O
7.8.9Mogánite
SiO
 
2

Other Names for Cristobalite

Synonyms:
α-Cristobaliteb-CristobaliteLow CristobaliteLussatine
Other Languages:
Dutch:Cristobaliet
Estonian:Kristobaliit
French:Cristobalite
German:Cristobalit
α-Cristobalit
b-Cristobalit
Cristobalitchalcedon
Lussatit
Tiefcristobalit
Italian:Cristobalite
Japanese:クリストバライト
Polish:Krystobalit
Portuguese:Cristobalita
Romanian:Cristobalit
Russian:Кристобалит
Simplified Chinese:方英石
白矽石
Spanish:α-Cristobalita
b-Cristobalita
Cristobalita
Lussatita
Ukrainian:Кристобаліт

Other Information

Thermal Behaviour:Inverts from high cristobalite at 268C.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Cristobalite

Reference List:

- +
Murdoch, Joseph (1942) Crystallographic notes, cristobalite, stephanite, natrolite. American Mineralogist: 27: 500-506.

Henderson, J.H., Jackson, M.L., Syers, J.K., Clayton, R.N., Rex, R.W. (1971) Cristobalite Authigenic origin in relation to montmorillonite and quartz origin in bentonite. Clays and Clay Minerals: 19: 229-238.

Murata, K.J., Nakata, J.K. (1974) Cristobalite stage in the diagenesis of diatomaceous shale. Science: 184: 567-568.

Richet, P., Bottinga, Y., Deniélou, L., Petitet, J.P., Téqui, C. (1982) Thermodynamic properties of quartz, cristobalite, and amorphous SiO2: drop calorimetry measurements between 1000 and 1800 K and a review from 0 to 2000 K. Geochimica et Cosmochmica Acta: 46: 2639-2658.

Internet Links for Cristobalite

Search Engines:
  • Look for Cristobalite on Google
  • Look for Cristobalite images on Google
  • External Links:
  • Look for Cristobalite on Webmineral
  • Look for Cristobalite on Athena Mineralogy
  • Look for Cristobalite on Wikipedia
  • Look for Cristobalite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Cristobalite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Cristobalite specimens for sale - minfind.com
  • Search for Cristobalite on Well-Arranged Molecules
  • Wilensky Fine Minerals
  • Buy from McDougall Minerals
  • Buy RARE Minerals from Rocks of Africa
  • Rare and Unusual minerals at Mineralogical Research Company
  • Fine Minerals from Weinrich Minerals, Inc.
  • Buy from David K Joyce minerals
  • Fabre Minerals - search for Cristobalite specimens
  • Buy fine minerals and gemstones from Pala International
  • rare and unusual minerals mainly crystallized
  • Jobs:
  • Mining & Geology Jobs
  • Localities for Cristobalite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Mineral and/or Locality  
    Search Google  
    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: March 25, 2014 17:04:19
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds