Tectosilicates, or “framework silicates,” have a three-dimensional framework of silicate tetrahedra with SiO2 in a 1:2 ratio. This group comprises nearly 75% of the crust of the Earth.- Robert Monroe (Wikipedia)
Robert Allan Monroe (October 30, 1915 – March 17, 1995) was an American radio broadcasting executive who became known for his research into altered consciousness and for founding The Monroe Institute. His 1971 book Journeys Out of the Body is credited with popularizing the term “out-of-body experience”.