Sagenitic Biotite

The term "sagenitic texture" refers to the occurrence of slender, needlelike inclusions intersecting at angles of 60° and included in phlogopite, quartz, or other minerals. Although such acicular inclusions have long been thought to consist of rutile, titanite, hematite, tourmaline, zircon, apatite, or allanite. Sagenitic rutile form for exsolution processes in Ti-bearing Biotite as fine needles.

Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Optical Mineralogy : The Nonopaque Minerals by Phillips / Griffen
• E. WM. Heinrich (1956): Microscopic Petrografy. Mcgraw-hill book company,inc


Photo
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Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 10x (Field of view = 2mm)
biotiterutilata(3).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 10x (Field of view = 2mm)
biotiterutilata.jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 10x (Field of view = 2mm)
rutilosaginitico(1).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 20x (Field of view = 1mm)
rutilosaginitico(2).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 2x (Field of view = 7mm)
rutilosaginitico(3).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 2x (Field of view = 7mm)
rutilosaginitico(4).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 20x (Field of view = 1mm)
rutilosaginitico(5).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 20x (Field of view = 1mm)
rutilosaginitico(6).jpg

Sagenitic Biotite with needlelike inclusions of rutile. XPL image , 20x (Field of view = 1mm)
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Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 10x (Field of view = 2mm)
biotiterutilata(1).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 10x (Field of view = 2mm)
biotiterutilata(2).jpg

Sagenitic Biotite with needlelike inclusions of rutile. PPL image , 10x (Field of view = 2mm)