Hornblende

3D Model

Polyhedral model of the hornblende structure showing the monoclinic character. Si-tetrahedra (blue) form double chains parallel tothe Z-axis (vertical in the initial view). Iron and magnesium occupy the smaller (orange) octahedral sites, while calcium occupies the larger (cyan colour) distorted octahedral sites. The large ‘A’ site (yellow atom) may be vacant or occupied by sodium or potassium.

This model was uploaded via a vrml export from the freeware Vesta. Data for albite were downloaded from the American Mineralogist Crystal Structure Database.