Here's why:

* Silicate minerals are composed of silicon and oxygen, forming the fundamental building block known as the silicate tetrahedron (SiO₄).

* Framework silicates have a three-dimensional network of linked tetrahedra, where each oxygen atom is shared by two tetrahedra. This creates a strong, rigid structure. Quartz is a prime example of this structure, with its iconic crystalline form.

Other silicate mineral types include:

* Nesosilicates: Isolated tetrahedra (e.g., olivine)

* Sorosilicates: Double tetrahedra (e.g., epidote)

* Inosilicates: Chains of tetrahedra (e.g., pyroxene)

* Phyllosilicates: Sheets of tetrahedra (e.g., mica)