muscovite mica
DESCRIPTION
Muscovite Mica in details...TRANSCRIPT
MUSCOVITE MICA
BY- ASHISH RANJAN, 12411008
What is Mica?
Mica is a generic term applied to a group of rock-forming complex
aluminosilicate minerals having a sheet or plate like structure with varying
chemical composition and physical properties.
Types Of Mica
Of the nine common varieties in the mica group of minerals, the two principal
classes of Mica types of commercial importance are
Muscovite : K Al2 (Al Si3 O10 )(OH) 2 and
Phlogopite : K Mg3 (Al Si3 O10 )(OH) 2
Muscovite Mica
It is a hydrous potassium aluminium silicate with a predominance of
potassium. It ranges from colourless through browns to greens or reds.
Phlogopite Mica
It is a hydrous magnesium aluminium silicate with a predominance of
magnesium. It is commonly called as “Amber Mica” which varies in colour
from light silver to dark brown or amber.
Occurence
Muscovite is the most common mica, found in Granites,
Pegmatites, Gneisses, and Schists, and as a contact
metamorphic rock or as a secondary mineral resulting
from the alteration of Topaz, Feldspar, Kyanite, etc.
In Pegmatites, it is often found in immense sheets that
are commercially valuable.
Exploration and exploitation is successfully carried
by means of systematic vertical shaft and open cast
mining. The principal muscovite mica deposits are
chiefly found in the States of Jharkhand, Rajasthan
and Andhra Pradesh.
Jharkhand (formerly Bihar State) which produces the
world's finest muscovite mica well known throughout
the globe
Muscovite
Mica may be
divided into two
color groups :
RUBY MUSCOVITE
GREEN MUSCOVITE
Ruby Muscovite
Colour ranges from an almost white
through pink to a light ruby and
into shades of brownish ruby and
brown. It is produced in the Indian
States of Jharkhand and Rajasthan.
Green Muscovite
Ranges from light to pale green through yellowish
and olive green to a dark green. It is produced
in the Indian State of Andhra Pradesh.
Physical Properties
Lustre -Vitreous, Silky, Pearly
Diaphaneity (Transparency):Transparent,
Translucent
Colour:White to colorless, silvery-white, and tinged various colors by
impurities.
Streak:White
Hardness (Mohs): 2½
Cleavage:Perfect
Perfect on {001}.
Fracture:Micaceous
Crystal System: Monoclinic with a = 5.199Å, b = 9.027Å, c = 20.106Å
β = 95.78°
DISTINGUISHING SIMILAR MINERALS
Chlorite and Margarite - Not as elastic as Muscovite.
Biotite, Phlogopite - Usually darker in color, otherwise very difficult to
distinguish.
Lepidolite - Very difficult to distinguish from pink Muscovite.
Gypsum - Cannot be peeled into micaceous sheets, crystals usually
differently shaped.
Uses
THANK YOU
Muscovite is an extremely common mineral, some bright yellow and others with perfect star formations, come from the famous pegmatite localites in the Doce and Jequitinhonha Valleys in Minas Gerais Brazil. Specific localities include Divino das Laranjeiras ("stars"),Galileia, Governador Valadares, Conselheiro Pena, Jaguaracu, Aracuai, and Coronel Murta. Beautiful yellow Muscovite comes from the Davib Ost Farm, Karibib, Erongo, Namibia. Fine Muscovite plates, often associated with valuable pegmatitegemstones, come from the Shigar Valley and Skardu District in Northern Pakistan. Nellore, India, is famous for its Muscovite mines which have produced some of the worlds largest mica sheets. Xuebaoding Mountain, Pingwu, in Sichuan Province, China, provides excellent Aquamarine and Scheelite that are associated with beautiful Muscovite plates.
In the U.S., Muscovite is fairly common in the pegmatites of San Diego county, including Pala and Ramona. Rare Muscovitepseudomorphs after Tourmaline come from the Willow Spring Ranch, Oracle, Pinal Co., Arizona. A bright pink, lithium-rich variety comes from the Harding Mine, Taos Co., New Mexico; and gemmy green crystals from Lincoln Co., North Carolina. Other important localties include Mt Antero, Chaffee Co., Colorado; the Diamond Mica Mine, Keystone, Pennington Co., South Dakota; Shelby, Cleveland Co., North Carolina; and Bedford, Westchester Co., New York.
New England contains some important Muscovite in its famous pegmatites, specifically at Middlesex Co., Connecticut (East Hampton, Haddam, and Portland); Grafton Co., New Hampshire (the Palermo No. 1 Mine, Groton; and the Ruggles Mine, Grafton); Mt. Apatite, Auburn, Androscoggin Co., Maine; and Greenwood and Newry, Oxford Co., Maine.