Phlogopite
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Phlogopite is a yellow, greenish, or reddish-brown member of the mica family of phyllosilicates. It is also known as magnesium mica.
Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula... Wikipedia
Cleavage: Perfect basal (001)
2V angle: 16–20°
Birefringence: δ =0.0280–0.0450
Color: Brown, brownish red, dark brown, yellow, yellowish brown, green, white and gray
Crystal class: Prismatic (2/m); (same H-M symbol)
Crystal habit: Tabular, scaly masses, rarely perfect phenocryst tablets
Crystal system: Monoclinic
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