Metasilicates are derivatives of the acid H2SiO3; the constitutional formula is 0=Si(OH)2, like that of carbonic acid. Examples of metasilicates are:-

Wollastonite

Wollastonite.

Augite or Hornblende

Augite or Hornblende.

Jade

Jade.

The potassium salt is Leucite.