Olivine Structure

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay

At left is a polyhedral model of the olivine structure. The oxygens are in a nearly close-packed arrangement.

Si tetrahedra cap voids in the zigzag chains of Mg octahedra.

Here is a ball model of the structure. Blue atoms are oxygen, magenta are silicon, and yellow are magnesium.

The diagram below shows two layers of the structure, showing how successive layers are related.


The figure below shows how the magnesium atoms (yellow and green) relate to the silica tetrahedra (shown with blue oxygen atoms and magenta silicon).

All of these structures look quite nearly hexagonal, and in fact the b/c ratio of the unit cell is 1.71, not far from the square root of 3 (1.732). Thus the diagonal of the unit cell nearly forms a 30-60 right triangle with the two adjacent edges.

Return to Mineralogy-Petrology Index
Return to Thin-Section Index
Return to Crystals and Light Index
Return to Crystal Structures Index
Return to Mineral Identification Tables
Return to Professor Dutch's Home Page

Created 21 February 2002, Last Update