Microscope slides of Biotite Mica from Norway, these slides display the crystal structure of the mineral on a microscopic level which assists in the identification of this mineral in other slides. Biotite mica is a black, platy mineral which forms in sheets, it belongs to the mica group of minerals which also includes muscovite, phlogopite and lepidolite micas. Being a common phyllosilicate mineral, it is also found in many rocks, particularly of igneous and metamorphic origin, such as mica schist, gneisses and granites. The crystal system of mica in general is monoclinic and like other mica minerals, biotite has a perfect basal cleavage and consists of flexible sheets or lamellae, which easily flake off, with tabular to prismatic crystals. Each section is made to 30 microns thickness and the glass is 46 x 27 mm in size, supplied in a protective card sleeve with a label, ideal for microscopy & educational use.