Here's why:

* Jasper is a variety of chalcedony. Chalcedony is a cryptocrystalline form of silica (SiO2).

* Silica is a silicate. Silicates are minerals that contain the silicon-oxygen tetrahedron (SiO4) as their basic building block.

Therefore, jasper, being a form of chalcedony and composed of silica, is classified as a silicate mineral.