Final answer:
Silicates are the most abundant group of minerals in Earth's crust, making up approximately 90% of the crust. They are SiO4 based materials and have a complex structure based on the silicon-oxygen tetrahedron.
Step-by-step explanation:
The most abundant group of minerals in Earth's crust is silicates. Approximately 90% of the Earth's crust is made up of silicates, which are SiO4 based materials. Silicate minerals are structures based around the silicon-oxygen tetrahedron and are the largest, most interesting, and most complicated class of minerals.