The most simple type of silicates are the “nesosilicates”, those with isolated tetrahedrons SiO₄^4- (left). Each tetrahedron can bond iron or magnesium, both bivalent, forming the minerals known as Fayalite Fe₂SiO₄ and Forsterite Mg₂SiO₄, respectively. As the Fe and Mg percentage in the crystal lattices is variable, the minerals are referred to as Olivine “solid solution”, also know as Peridot. The mineralogical formula is (Fe,Mg)₂SiO₄, with variable content of the two minerals.

By adding one silica molecule to Olivines we obtain the silicates known as Pyroxenes, where tetrahedrons are spatially organized in chains, so that they’re called “inosilicates” (right). Bonded cations may be various: (Fe,Mg,Ca,Na,Al)Si₂O₆. For example, by adding silica SiO₂ to the magnesian Olivine “Forsterite” we have Mg₂SiO₄ + SiO₂ = Mg₂Si₂O₆, which is a Pyroxen known as Enstatite. Doing the same thing to the ferrous Olivine we would obtain Ferrosilite. In nature, we can find some calcium atoms in place of one iron or magnesium atoms. This would lead to Hedembergite or the more common Diopside. CaMgSi₂O₆.

Going on like that we could ideally obtain the double-chain inosilicates called “Amphiboles” (left), whose more complex formula contains the hydroxylic ion Si₈O₂₂(OH)₂^7- obtained by adding silica and water to a Pyroxene in high temperature and pressure environments typical of metamorphism.

Nesosilicates		|—————	Inosilicates	—————|
OLIVINES	+SiO2->	PYROXENES	+SiO2+H2O->	AMPHIBOLES
		(rombic)		(rombic)	Ferromagnesian
Mg2SiO4	+SiO2->	Mg2Si2O6	+SiO2+H2O->	Mg7Si8O22(OH)2
Forsterite		Enstatite		Antophyllite
Fe2SiO4	+SiO2->	Fe2Si2O6	+SiO2+H2O->	Fe7Si8O22(OH)2
Fayalite		Ferrosilite		Grunerite
		(monocline)		(monocline)	Calcic
		CaMgSi2O6	+SiO2+H2O->	Ca2Mg5Si8O22(OH)2
		Diopside		Tremolite
		CaFeSi2O6	+SiO2+H2O->	Ca2Fe5Si8O22(OH)2
		Hedembergite		Actinote
		(complex)		(complex)
					complex
		(Ca,Na)(Mg,Fe(Al)Si2O6	+SiO2+H2O->	NaCa2(Mg,Fe)5Si8O22(OH)2
		Omphacite (diopside+jadeite)		Horneblende (simplified)