Basalt consists of about 48-52% silica (SiO2). Other major elements in varying proportion include titanium (TiO2), aluminum (A2O3), iron (FeO or Fe2O3), manganese (MnO), magnesium (MgO), calcium (CaO), sodium (Na2O), potassium (K2O, and phosphorous (P2O5).

http://volcanoes.usgs.gov/Products/P...cks.html#oxide

Gitzo pulverises basalt, melts it and adds some pixie dust, then spins it into fibers. The result is a glass/metal composite fiber that is woven and laminated with epoxy into a tube structure. Then Gitzo PR takes over...