Melilite (Ca,Na)2(Al,Mg,Fe++)(Si,Al)2O7 is a true sorosilicate with a very simple structure. It has tetragonal symmetry. The view below looks down the c-axis. Silica tetrahedra are purple, aluminum tetrahedra are ywllow and calcium ions are green. As shown by the formula, considerable cation substitution is possible.
A view normal to the c-axis, below. Layers of tetrahedra alternate with layers of larger cations.
Created 22 April 2013, Last Update 08 Jul 2013
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