SAPPHIRINE is a principal constituent of certain high grade silica-deficient metamorphic rocks at Fiskenaesset, West Greenland, where it occurs with cordierite, corundum, anorthite and biotite.

These rocks are mostly made of silicate minerals that crystallize ... The last group of rocks is called metamorphic, because ...

Silicate rock makes up the Earth's crust and the towering bulk of its mountain ranges. Igneous and metamorphic rocks are loaded with it. Sand, too, is mostly grains of silicates weathered out of ...