FLUOROKINOSHITALITE AND FLUOROTETRAFERRIPHLOGOPITE : NEW SPECIES OF FLUORO-MICA FROM BAYAN OBO, INNER MONGOLIA, CHINA

Two new species of F-mica, fluorokinoshitalite (BaMg_3Al_2Si_2O_ F_2) and fluorotetraferriphlogopite (KMg_3Fe^Si_3O_ F_2) occur in Bayan Obo, Inner Mongolia, China. They form subhedral to euhedral platy crystals in metamorphosed carbonate rocks. They are associated with phlogopite, yangzhumingite, a...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Clay Science 2011, Vol.15(1), pp.13-18
Hauptverfasser: MIYAWAKI, RITSURO, SHIMAZAKI, HIDEHIKO, SHIGEOKA, MASAKO, YOKOYAMA, KAZUMI, MATSUBARA, SATOSHI, YURIMOTO, HISAYOSHI, YANG, ZHUMING, ZHANG, PEISHAN
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Two new species of F-mica, fluorokinoshitalite (BaMg_3Al_2Si_2O_ F_2) and fluorotetraferriphlogopite (KMg_3Fe^Si_3O_ F_2) occur in Bayan Obo, Inner Mongolia, China. They form subhedral to euhedral platy crystals in metamorphosed carbonate rocks. They are associated with phlogopite, yangzhumingite, and rare earth minerals such as bastnasite-(Ce), cordylite-(Ce), monazite-(Ce), fluorbritholite-(Ce) and huanghoite-(Ce). Fluorokinoshitalite is transparent and colorless with white streak and pearly luster. Cleavage is perfect on {001}. The calculated density is 3.235g cm^. Fluorotetraferriphlogopite is brown in color with white to pale brown streak. It is transparent showing pearly luster and perfect cleavage on {001}. The hardness is 3-4 on the Mohs scale. The calculated density is 2.966g cm^. This mineral is optically biaxial (-) with n=1.576 (min.)-1.582 (max.). It shows reverse pleochroism (Z'=colorless, X'=light brown). Electron microprobe analyses with SIMS for Li gave empirical formulae (based on 12 anions); (Ba_Na_K_)(Mg_Fe^_Ti_) (Si_Al_Fe^_)O_ [F_(OH)_] and (K_Na_Ba_)(Mg_Li_Fe^__Mn_)(Si_Fe^_Al_)O_ [F_(OH)_] for fluorokinoshitalite and fluorotetraferriphlogopite, respectively. The lattice parameters were refined in the monoclinic system (C2/m) with the XRD data obtained with an IP-Gandolfi camera as; a=5.3161 (11), b=9.2082(15), c=10.044(2) Å, β=100.158(18)°, V=483.97(17) Å^3 (fluorokinoshitalite) and a=5.325(3), b=9.217(5), c=10.192(7) Å, β=100.03(5)°, V=492.6(5) Å^3 (fluorotetraferriphlogopite).
ISSN:0009-8574
2186-3555
DOI:10.11362/jcssjclayscience.15.1_13