Muscovite
Mica; Sheet Silicates
Monoclinic (-)
Relief - moderate
Colour - colourless
RI - 1.552-1.618
Birefringence - 0.036-0.049
Interference colours - 3rd order
Extinction - straight, mottled
Comments
Colourless crystals of muscovite, showing moderate relief and perfect cleavage.
PPL
Granite, Megilligar Rocks
The same field of view as above showing high birefringence.
XPL
Granite, Megilligar Rocks
muscovite (pink and yellow flakes) in a marble
XPL
Muscovite defining a strong schistosity
XPL
Arna Unit, Argos, Greece