HORNBLENDE, QUARTZ, FELSPAR, PYROXENES, AMIPHOBLE, MICA GROUP
Table of Contents
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