Noun
The word is derived from tetrahedron
Correspondingly, a regular octahedron is the result of cutting off from a regular tetrahedron, four regular tetrahedra of half the linear size (i.e. rectifying the tetrahedron). Source: Internet
Dyar and Gunter, p. 105 Orthosilicates (or nesosilicates) have no linking of polyhedra, thus tetrahedra share no corners. Source: Internet
At the next iteration, the side-length is halved: : and there are 4 such smaller tetrahedra. Source: Internet
Cleavage is not a universal property among minerals; for example, quartz, consisting of extensively interconnected silica tetrahedra, does not have a crystallographic weakness which would allow it to cleave. Source: Internet
BeCl 2 and BeBr 2 have chain structures with edge-shared tetrahedra. Source: Internet
Disilicates (or sorosilicates) have two tetrahedra sharing one oxygen atom. Source: Internet