They are by far the
largest group of all minerals on the Earth.
The group is so large
it is further divided into seven sub-groups.
These are tectosilicates
(aka framework silicates), phyllosilicates (aka sheet silicates),
double chain silicates, single chain silicates, cyclosilicates (aka
ring silicates), disilicates (aka sorosilicates) and nesosilicates (aka
are the group
of silicates that contains the most abundant rock forming minerals.
It contains the different forms of quartz
such as rock crystal, citrine, amethyst, aventurine, cat's eye, tiger's
eye, and rutliated, rose, milky, smoky, and phantom quartz; chalcedony,
agate and opal; and the groups of feldspars,
feldspathoids and zeolites.
Phyllosilicates are the minerals that are composed of sheets.
bonding is strong within the sheets and weak between them, making the
sheets breaking off from each other quite easily. The group contains
(muscovite, biotite etc) and clay
minerals (kaolinite, illite, montmorillonite
By Penny Higgins via Flickr.com
Double chain silicates include a group of very common silicate minerals
such as hornblende, anthophyllite, gerdite, cummingtonite, tremolite,
glaucophane and riebeckite. The minerals in this group are
dark-coloured, mafic, ferro-magnesian minerals.
Single chain silicates include another group of very
common silicate minerals -pyroxenes
orthopyroxene, pigeonite, diopside, hedenbergite, augite, aegerine,
jadeite, omphacite and spodumene. The minerals in this group are
also dark-coloured, mafic, ferro-magnesian minerals.
= Ring Silicates
Cyclosilicates have a ring-like atomic structure. This group contains beryl, cordierite
(elbite, verdelite, schorl, achroite, rubellite,
buergerite, dravite, and chromdravite).
Beryl and tourmaline are
By Ian Geoffrey Stimpson via Flickr.com
The group of disilicates contains about 70 minerals such as allanite,
clinozoisite, axinite, pumpellyite and hemimorphite, although
the only common ones are the groups of epidote
are the group with isolated silica tetrahedrae. The crystal sides are
of equal length and they are relatively hard, heavy and have poor
cleavage. The group includes some well known minerals such as olivine and garnet, aluminium
silicates (kyanite, sillimanite and andalysite), topaz, titanite,
staurolite, chloritoid, and zircon
- the oldest mineral found on the Earth.