Bytownite
A variety of Anorthite
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About Bytownite
Formula:
(Ca,Na)[Al(Al,Si)Si2O8]
Albite : anorthite molar ratio ranges from 10 : 90 to 30 : 70.
Colour:
Colourless, grey, greenish-white, or white
Lustre:
Sub-Vitreous
Hardness:
6 - 6½
Crystal System:
Triclinic
Name:
Named after its locality ("Bytown," now Ottawa, Ontario, Canada).
A plagioclase feldspar with an albite : anorthite molar ratio ranging from 10 : 90 to 30 : 70.
May show labradorescence (compare labradorite).
The original material, a greenish-white substance, was found in a boulder near Bytown (now Ottawa), and later shown to be a mixture (Robert A. A. Johnston, 1915). This locality now appears to have been lost. Additionally, the original specimens are either extremely rare or no longer exist in collections. Gemmy feldspar pieces are, on occasion, falsely attributed to the original bytownite locality.
Visit gemdat.org for gemological information about Bytownite.
May show labradorescence (compare labradorite).
The original material, a greenish-white substance, was found in a boulder near Bytown (now Ottawa), and later shown to be a mixture (Robert A. A. Johnston, 1915). This locality now appears to have been lost. Additionally, the original specimens are either extremely rare or no longer exist in collections. Gemmy feldspar pieces are, on occasion, falsely attributed to the original bytownite locality.
Visit gemdat.org for gemological information about Bytownite.Unique Identifiers
Mindat ID:
815 (as Bytownite)
246 (as Anorthite)
246 (as Anorthite)
Long-form identifier:
mindat:1:1:815:0 (as Bytownite)
mindat:1:1:246:6 (as Anorthite)
mindat:1:1:246:6 (as Anorthite)
Classification of Bytownite
16.10.1
16 : Silicates Containing Aluminum and other Metals
10 : Aluminosilicates of Ca and alkalis
16 : Silicates Containing Aluminum and other Metals
10 : Aluminosilicates of Ca and alkalis
Pronunciation of Bytownite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Bytownite
Sub-Vitreous
Colour:
Colourless, grey, greenish-white, or white
Streak:
White
Hardness:
6 - 6½ on Mohs scale
Cleavage:
Perfect
on [001], good on [010]
on [001], good on [010]
Fracture:
Step-Like
Optical Data of Bytownite
Type:
Biaxial (+/-)
RI values:
nα = 1.563 - 1.572 nβ = 1.568 - 1.5784 nγ = 1.573 - 1.583
2V:
Measured: 86° , Calculated: 80° to 88°
Max. Birefringence:
δ = 0.010 - 0.011
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
Surface Relief:
Moderate
Dispersion:
r > v strong
Chemistry of Bytownite
Mindat Formula:
(Ca,Na)[Al(Al,Si)Si2O8]
Albite : anorthite molar ratio ranges from 10 : 90 to 30 : 70.
Albite : anorthite molar ratio ranges from 10 : 90 to 30 : 70.
Element Weights:
Crystallography of Bytownite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 8.178 Å, b = 12.870 Å, c = 14.187 Å
α = 93.5°, β = 115.9°, γ = 90.63°
α = 93.5°, β = 115.9°, γ = 90.63°
Ratio:
a:b:c = 0.635 : 1 : 1.102
Unit Cell V:
1,339.53 ų (Calculated from Unit Cell)
Z:
8
Synonyms of Bytownite
Calcic plagioclase (in part)
Other Language Names for Bytownite
Common Associates
Associated Minerals Based on Photo Data:
| 3 photos of Bytownite associated with Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| 3 photos of Bytownite associated with Pyrrhotite | Fe1-xS |
| 1 photo of Bytownite associated with Diallage | |
| 1 photo of Bytownite associated with Quartz | SiO2 |
| 1 photo of Bytownite associated with Anorthite | Ca(Al2Si2O8) |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Bytownite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Bytownite
mindat.org URL:
https://www.mindat.org/min-815.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
References for Bytownite
Reference List:
Jin, Shiyun; Wang, Xiaoping; Xu, Huifang (2018) Revisiting the I-1 structures of high-temperature Ca-rich plagioclase feldspar – a single-crystal neutron and X-ray diffraction study. Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials, 74 (2). 152-164 doi:10.1107/s2052520618003219
Localities for Bytownite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Albania | |
| Váczi-Lovász et al. (2024) |
Algeria | |
| Lustrino et al. (2016) |
| Eur. J. Mineral. |
Angola | |
| Eur. J. Mineral. |
Antarctica | |
| Mukherjee et al. (1986) |
| Smellie et al. (1984) |
Argentina | |
| 146-157 (Jan/Feb 1971) +1 other reference |
| Pagano et al. (2016) +2 other references |
Armenia | |
| Nazarov et al. (1995) |
Australia | |
| Mason B. (1979) |
| Garcia et al. (1978) |
| Birch (1999) |
| Pearson et al. (1991) |
| Zia U. Bajwah |
| Huckitta 1996 |
| Weisberg et al. (2009) |
| Taheri |
| 263-269. ( Sept 1986) +1 other reference |
| McCall et al. (1966) |
| Trommsdorff et al. (1968) |
| New Material From +1 other reference |
Austria | |
| H. Meixner: 32 (3) |
| Niedermayr et al. (1995) | |
| Meixner (1967) |
| Niedermayr et al. (1995) |
| Exel (1993) |
| Carswell et al. (1989) |
| Libowitzky et al. (2012) |
| Heritsch (1963) |
| Exel (1993) |
| Postl et al. (1996) |
Bangladesh | |
| Powell (1971) |
Belgium | |
| de Béthune (1977) +1 other reference |
Burkina Faso | |
| Grossman et al. (2000) +1 other reference |
Canada | |
| Telus et al. (2014) |
| - (n.d.) |
| Bernier (1990) |
| |
| OGS OFR5329 |
| António Manuel Ináçio Martins. |
| T. Tagai et al. |
| Olivier Langelier Collection |
China | |
| |
| Jiyue Xue et al. (1999) |
| Shanming Fu et al. (2005) |
| Lishe Wang et al. (2008) |
| Jingwen Mao et al. (2006) |
| Youbin Liang (1981) |
| Yiming Zhao et al. (2008) |
| Xiyue Wang et al. (1987) |
| Bao Peisheng et al. (2007) |
| Fengmei Chai et al. (2006) |
| Ruan +3 other references |
Costa Rica | |
| |
Cuba | |
| Roesler (1917) |
Czech Republic | |
| Ackerman et al. (2025) |
| von Engelhardt (1963) |
El Salvador | |
| ... |
Ethiopia | |
| exemple de l'Afar. Bulletin de la Société Géologique de France (5-6) +8 other references |
Finland | |
| Barkov et al. (1999a) |
| www.gemmo.eu (n.d.) |
France | |
| M. Christophe Michel-Lévy |
| F. André and J. Béhien |
| F. André and J. Béhien | |
| F. André and J. Béhien | |
| F. André and J. Béhien | |
| F. André and J. Béhien |
| Delesse (1848) +1 other reference |
| Blais et al. (1997) +2 other references |
| Lacroix (1904) |
| Ch. Lefèvre and Ph. Cocusse |
| Lacroix (1910) |
| Mason B. (1979) |
| Abdel-Karim et al. (1989) |
Germany | |
| Mason B. (1979) |
| Weiß (1990) |
| |
| Ramdohr (1969) |
| Blass et al. (2006) |
Greece | |
| Liati et al. (1994) |
Greenland | |
| Deer (1963) |
Hungary | |
| Kovács et al. (2003) |
| Kohút et al. (2019) |
Iceland | |
| Blake (1966) |
India | |
| Leelanandam |
| Mohammad et al. (2022) |
| Bhattacharjee et al. (2012) |
| Mason B. (1979) |
| Rout et al. (2022) |
| Mineralogical Studies of Metasomatized ... +1 other reference |
| Shukla et al. (1997) |
| Sharma et al. (2006) |
| Schwartz et al. (2001) |
| Mason (1963) |
Indian Ocean | |
| Maciąg et al. (2019) | |
Indonesia | |
| Dani Lukman Hakim (2016) |
| Abdurrachman et al. (2012) |
Iran | |
| Powell (1971) |
Italy | |
| ... |
| Franciosi et al. (2019) |
| Stara et al. (1999) |
| S. Tonarini et al. |
| Civetta L. et al. (1998) |
Japan | |
| unpublished analysis |
| - (n.d.) |
| Petrov (n.d.) |
| Masaru Yamaguchi (1964) |
| Masaru Yamaguchi (1964) |
| Itaru Ogitsu: Origin of composition ... |
Kenya | |
| Scott (1980) +4 other references |
Kyrgyzstan | |
| Soloviev (2011) |
Lithuania | |
| Mason B. (1979) +1 other reference |
| Mason B. (1979) +1 other reference |
Madagascar | |
| Delbos (1955) |
| Lacroix (1922) |
| Groat +5 other references |
Mauritania | |
| Duke (1978) |
Mexico | |
| Collectors Edge specimens |
| ... |
| Ruzicka et al. (2006) |
Mongolia | |
| Savina et al. (2020) |
| Peretyazhko et al. (2017) |
Morocco | |
| JÉRÉMINE (1955) +1 other reference |
New Zealand | |
| Benson (1942) +1 other reference |
Nigeria | |
| Mason (1967) |
Norway | |
| ... |
| Bøe (2001) |
| Geological Survey of Norway. The ... |
Pacific Ocean | |
| R. Hekinian et al. |
Poland | |
| Lis et al. (1986) |
| www.kamienna-gora.eu (2020) |
| Lis et al. (1986) |
| Białowolska A. +1 other reference | |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) | |
| Powell (1971) |
Portugal | |
| L. Miguel Gaspar and Carlos M. C. Inverno (2000) |
| Gaspar et al. (2000) |
Russia | |
| Kepezhinskas et al. (2023) |
| Spiridonov et al. (2019) |
| Spiridonov et al. (2019, April) | |
| Spiridonov et al. (2018) | |
| Kislov +1 other reference | |
| Mazurov et al. (2007) |
| Soloviev et al. (2022) |
| Migdisova et al. (1988) |
| Kokh et al. (2023) |
| Shchukina et al. (Vol. 473, No. 1, pp. 333-337) |
| Sklyarov et al. (2023) |
| Kolova et al. (2023) |
| Sushchenko et al. (2023) |
| Huber et al. (2015) |
| Steele et al. (1982) |
| Erokhin et al. (2018) |
| Eur. J. Mineral. |
| [World of Stones 12:49] | |
| Trunilina et al. (2021) |
| Shadenkov (1989) |
| Kostin (2021) | |
| Ganino et al. (2019) |
| Mason B. (1979) |
Saudi Arabia | |
| Abuamarah et al. (2023) |
| Fredriksson et al. (1986) |
Slovakia | |
| Koděra (1986) |
| Koděra (1986) |
| Yáñez et al. (2021) +1 other reference |
| Koděra (1986) |
| Duda |
| Ďuďa |
| Duda et. all. |
South Africa | |
| Mineralogical Magazine 38 (293) +1 other reference |
| Labotka et al. (1980) |
| Ndhlovu (2017) |
| Kottke-Levin et al. (2008, December) |
South Korea | |
| Lee (ed) +7 other references | |
| Atsuo Harumoto (1970) |
Spain | |
| B. Azambre et al. +1 other reference |
| B. Azambre et al. +1 other reference |
| Mason (1963) |
| B. Azambre et al. +1 other reference |
| B. Azambre et al. +1 other reference |
| B. Azambre et al. +1 other reference |
| Majarena Serrano (2015) |
| Alfonso et al. (2012) |
| Carlos Anaut analysis (Baikal Geo) |
| Mason et al. (1973) |
Sweden | |
| Agarwal et al. (2016) |
| Hjelmqvist (1950) |
Switzerland | |
| Stalder et al. (1998) |
Tanzania | |
| Hintze (2010) |
| Hsu et al. (1997) |
UK | |
| Marr (1900) |
| J. C. Phillips et al. (2013) |
| Harrison (1975) | |
| Livingstone (1988) |
| Miller et al. (1965) |
Ukraine | |
| Spiridonov et al. (2019) |
| Ivanova et al. (1993) |
USA | |
| Anthony et al. (1995) |
| Haxel et al. (2023) |
| Woodford et al. (1941) |
| U.S. Geological Survey Professional ... +1 other reference |
| Mason (1963) |
| Januzzi et al. (1976) |
| Connolly et al. (2006) |
| 34-37 +2 other references |
| Rocks & Min.:64:198. |
| Cook (1978) | |
| Cook (1978) |
| Fuchs L H (1967) |
| Olsen et al. (1987) |
| King et al. (1994) |
| W. B. Thompson et al. (2005) |
| Mason B. (1979) |
| Heinrich et al. (2004) |
| Heinrich et al. (2004) |
| Heinrich et al. (2004) | |
| McCallum (1996) |
| Rifai +4 other references |
| Meyers et al. (1956) |
| Northrop et al. (1996) |
| Northrop et al. (1996) | |
| Northrop et al. (1996) |
| Northrop et al. (1996) | |
| Northrop et al. (1996) |
| Jahns et al. (1944) |
| Northrop et al. (1996) |
| Steele et al. (1982) |
| Wood (1996) |
| Harry y.MvSween |
| Speer (1981) |
| McSween et al. (1984) |
| Hadley | |
| Absher and McSween H.Y Jr |
| McSween Jr et al. (1984) |
| Colney (1962) | |
| Hess et al. (1949) |
| McSween et al. (1984) |
| Brearley et al. (1998) |
| - (2005) |
| Howard (2008) |
| Mineral collecting in Pennsylvania +2 other references |
| Prince et al. (2004) |
| Prince et al. (2004) | |
| Roberts et al. (1965) |
| Buchanan et al. (1996) +1 other reference |
| Donnelly (1962) |
| Heyse (1975) |
| Dietrich (1990) |
| Dietrich (1990) |
| Jérome et al. (1972) |
| Thompson et al. (2015) +1 other reference |
| Cannon (1975) |
| Cordua (1998) |
Zimbabwe | |
| Meck et al. (2011) |
Dorado Mine, Casas Grandes Municipality, Chihuahua, Mexico