Like other micas, biotite has a crystal structure described as TOT-c, meaning that it is composed of parallel TOT layers weakly bonded to each other by cations (c). The TOT layers in turn consist of two tetrahedral sheets (T) strongly bonded to the two faces of a single octahedral sheet (O).

2023年9月2日 · Crystal Structure: Biotite belongs to the phyllosilicate class of minerals, characterized by its sheet-like structure. Its crystal structure consists of layers of silicon-oxygen (Si-O) tetrahedra, bonded together with sheets of aluminum-oxygen (Al-O) octahedra.

A common, widespread, rock-forming mineral, biotite is a significant mineral in granites, diorites, and igneous pegmatites. In pegmatites, biotite crystals can be very large. It also occurs in schists, gneisses, and hornfels that resulted from either regional or contact metamorphism.

Biotite: Mineral information, data and localities. K (Fe2+/Mg)2(Al/Fe3+/Mg/Ti) ( [Si/Al/Fe]2Si2O10) (OH/F)2. A slash in the formula indicates different elements can occur in this position but without assumption on priority. Trioctahedral mica Group > Mica Group > Phyllosilicate Group.

Multiple crystals of biotite (browns) in a rhyolite associated with feldspar and quartz (white, transparent). Biotite shows variable hues of brown due to the strong pleochroism and its color changes with its orientation with respect to the polarizer.

Biotite–K(Mg,Fe)3AlSi3O10(OH)2–is a dark, iron-rich mica that has a monoclinic crystal system. The octahedral layer is entirely occupied by Mg2+ and Fe2+ and the mineral is therefore trioctahedral, since all octahedra are occupied.

Biotite crystal structure, including interactive 3D view, microphotographs, and thin sections

2005年7月14日 · Open the Crystal Structures Library on the CrystalMaker disc, and click on Minerals > Silicates > Sheet Silicates > Mica Group > Tri-octahedral > Biotite.