QUARTZ GROUP, HORNBLENDE, QUARTZ, FELSPAR, PYROXENES, AMIPHOBLE, MICA GROUP

QUARTZ GROUP

After feldspar, quartz is the mineral that is most prevalent in the crust of the Earth. It can be found in almost all sedimentary, metamorphic, and acidic rocks. It is a crucial component of silica-rich felsic rocks like rhyolites, granodiorites, and granites.

PHYSICAL PROPERTIES OF QUARTZ:

CRYSTAL SYSTEM: Hexagonal HABIT: Crystalline or amorphous

FRACTURE: Conchoidal

HARDNESS: 7

SPECIFIC GRAVITY:  2.65-2.66(LOW)

STREAK: No

TRANSPARENCY: Transparent/semi-transparent/opaque

POLYMORPHISM TRANSFORMATION:

Quartz ,tridymite,crystotallite,melt

COLOURED VARIETIES:

Pure quartz is always colourless and transparent

Presence of impurities the mineral showing colour they

Amethyst: purple or violet

Smoky quartz: shades of grey

Milky quartz: light brown, pure white, opaque

Rose quartz: rose

FELSPAR GROUP

Of all minerals, it is the most prevalent. More than 50% of the weight of the earth’s crust is made with it. It is a silicate mineral that is non-metallic.

CHEMICAL COMPOSITION:

Potash feldspar  KAlSi3 O8

Soda-lime feldspar  NaAlSi3O8 (OR) CaAl2Si2O8

VARITIES OF POTASH

FELSPAR: Orthoclase

Sanidine

Microcline

SODA LIME FELSPAR:

Albite

Oligoclase

Andecine

Amarthitie

Labrodorie

GENERAL PHYSICAL:

CRYSTAL SYSTEM: monoclinic,triclinic

HABIT: Tabular (crystalline)

CLEAVAGE: Perfect( 2- directional)

PYROXENES GROUP

It is a significant group of minerals that form rocks. They frequently appear in igneous and metamorphic rocks with dark colors. Calcium, magnesium, iron, and silicates are abundant in them. It demonstrates silicate in a single chain structure. Orthopyroxene and clinopyroxene are the two subtypes. It is founded on atomic structure within.

ORTHOPYROX ENE: Enstatite

(MgSiO3)

Hyperthene [(Mg,Fe)SiO3]

CLINOPYROXENE: PYROXENES

Augite [(Ca, Na) (Mg, Fe, Al) (Al,

Si)2O6] Diopside [CaMgSi2O6]

Hedenbergite[CaFeSi2O6]

AUGITE:

CRYSTAL SYSTEM: Monoclinic

HABIT: Crystalline

CLEAVAGE: Good ( primastic cleavage)

FRACTURE: Conchoidal

COLOUR: shades of greyish green and black

LUSTRE: vitreous

HARDNESS: 5-6

SPECIFIC GRAVITY: medium

STREAK:      white

OCCURRENCE: ferro magnesium mineral of igneous rock (dolerite)

USES: rock forming mineral

COMPOSITON: [(Ca, Na) (Mg, Fe, Al) (Al, Si)2O6]

TRANSPARENCY: Translucent/opaque

AMIPHOBLE GROUP

These and the Pyroxene Group are closely related. It exhibits a silicate double chain structure. rich in Mn, Na, K, and H, as well as calcium, magnesium, and iron oxide.

CLASSIFICATION:

1.     Orthorhombic

2.     Monoclinic

a.      Hornblende

b.     Tremolite

c.       Actinolite

HORNBLENDE:

A complicated inosilicate mineral series includes hornblende. Although the name is used to refer to a dark amphibole, it is not a recognised mineral in and of itself.

(COMPOUND-COMPLEX SILICATE) CRYSTAL SYSTEM: Monoc;inic

HABIT: crystalline

CLEAVAGE:good(prismatic) FRACTURE: conchoidal

COLOUR: dark green, dark brown black

LUSTRE: vitreous

HARDNESS: 5 to 6

SPECIFIC GRRAVITY: 3 to 3.5 (medium)

STREAK: colourless or white

COMPOSITION: hydrous silicates of Ca, Na,

Mg, Al TRANSPARENCY: translucent/opaque

OCCURRENCE: found in igneous rocks

USES: road material

MICA GROUP (mica mineral)

form-sheet-like architecture is capable of being split into very thin sheets in one direction. Magnesium and aluminum are abundant. fill 4% of the earth’s crust.

Any of the hydrous potassium, aluminum silicate minerals, including mica. A two-dimensional sheet or layer structure can be seen in this particular phyllosilicate. The three main types of rocks—igneous, sedimentary, and metamorphic—all contain micas, which are the main minerals responsible for the formation of those rocks.

HORNBLENDE:

(COMPOUND-COMPLEX SILICATE) CRYSTAL SYSTEM: Monoc;inic

HABIT: crystalline

CLEAVAGE:good(prismatic) FRACTURE: conchoidal

COLOUR: dark green, dark brown black

LUSTRE: vitreous

HARDNESS: 5 to 6

SPECIFIC GRRAVITY: 3 to 3.5 (medium)

STREAK: colourless or white

COMPOSITION: hydrous silicates of Ca, Na,

Mg, Al TRANSPARENCY: translucent/opaque

OCCURRENCE: found in igneous rocks

USES: road material