The inosilicates (chain silicates) or metasilicate chains are a bit like sorosilicates in that they are formed by each silica tetrahedron sharing two O_2- ions. However in this case the tetrahedra form infinite chains rather than pairs. The Si to O ratio is exactly 1 to 3. The chains can be simple such as in the Pyroxene family or more complex whereby different O^2- sharing positions give rise to linear chains that lack the symmetry of the former. Wollastonite and related minerals belong to this group. In both cases the long chains are aligned and held together by metal ions. In general Inosilicates have a prismatic, radiating or fibrous crystal habit along the direction of the chains. The direction and width of the chains are reflected in the cleavage properties, which are very characteristic and assist identification. The single chain silicates are a major group of rock forming minerals and are therefore greatly studied.

Double chain silicates, are a special class of the inosilicates. They differ from the single chain family by the fact that exactly half the tetrahedra in one infinitely long chain are cross-linked with half of those those in the other. Thus the minerals contain pairs of chains aligned and held together by metal ions. The group is frequently referred to as the Amphiboles and includes a series of important minerals that occur in igneous and metamorphic rocks. Because of the additional O^2- sharing the Si to O ratio is 4 to 11 and the general chemical formula is WX₂Y₅Si₈O₂2.(OH)₂, in which W is typically Sodium or Potassium, X is Calcium or Magnesium and Y tends be a transition metal such as Manganese, Iron or Titanium. As with single chain minerals the structural alignment crystal tends to favour prismatic, radiating or fibrous habits along the direction of the chains.