Classification of minerals

Course Title: Earth Science
Paper Title: MINERALOGY
Classification of MineralsClassification of Minerals
By
Prof.A. Balasubramanian
Centre for Advanced Studies in Earth Science
University of Mysore, India

Table of ContentsTable of Contents
 Introduction
 Crustal abundance of elements
 Chemical classification of
minerals
 Native elements
 The Standard Sulfides
 Halogenides, Oxyhalides &
Hydroxyhalides
 Oxides and Hydroxides
 Carbonates and Nitrates
 Borates
 Sulfates, Selenates,
Chromates, Molybdates,
Wolframates & Niobates
 Phosphates, Arsenates,
Vanadates & Polyvanadates
 Silicates
 Organic Compounds
 Conclusion.

 After attending this module, the user would be able
to know and explain the chemical classification of
minerals and the types of minerals belonging to
various classes and groups.
 The mineral kingdom is a very vast area in the
subject of earth sciences. Mineralogy is a perfect
physical science.
Objectives
(…Contd)

 About two thousand dominant minerals are popular
and existing over the world, which are known for
their unique properties.
 The study of the chemical classification of minerals is
an essential topic in the subject of mineralogy.
Objectives

 Lithosphere is the solid layer of the planet earth. It is
the rocky segment, holding all natural resources
including the energy resources, water resources,
mineral resources and the biotic resources.
Everything is existing, on earth, for human survival.
Introduction
(…Contd)

 Earth’s economic resources include thousands of
minerals belonging to the Mineral Kingdom.
 Every segment of the human society uses the
mineral resources, in one form or the other,
everyday, directly or indirectly. There are many
minerals which have commercial and industrial
importance.
Introduction
(…Contd)

 While studying the minerals, the classification of
minerals becomes a basic priority as there are
numerous groups occurring in different parts of the
world. There is a need to classify the minerals and
study their properties. This module highlights the
widely used chemical classification of minerals.
Introduction

The Earth’s crust is dominated by eight abundant chemical
elements. They are :
Oxygen 47%
Silicon 27%
Aluminum 8 %
Iron 5%
Calcium 3.6%
Sodium 2.8%
Potassium 2.6 %
Magnesium 2 % and all other elements about 1 %.
Crustal abundance of elements
(…Contd)

 Silicon and oxygen are the two most abundant
elements present in the earth’s crust. The other
elements, following these two, are aluminium, iron,
calcium, sodium, potassium, magnesium, hydrogen,
phosphorous, barium, and strontium.
 It is to be noted that the metals like copper, lead,
zinc, nickel, and tin which play an important role in
all our modern technology, are present only in very
small proportions.
(…Contd)

 The most abundant minerals in the earth's crust are
the silicates. Non-silicates constitute less than 10%
of the Earth's crust.
 The most common non-silicates are the carbonates,
the oxides, and the sulfides. There are also naturally
occurring phosphates and salts.

The World of Minerals
 Minerals are naturally formed elements or
compounds, having a definite chemical composition
and, usually, a characteristic crystal form.
 Minerals are valuable resources for live support
activities of the human population. Minerals are
naturally occurring inorganic substances.
(…Contd)

 Every mineral can be identified by several of its
physical properties and crystal chemistry.
 There are nearly 3700 minerals occurring on the
earth, out of which about two dozen minerals are
common, making upto 90% of the mineral
constituents in the earth’s crust.
(…Contd)

 Minerals may be composed of a single element, like
gold (Au) or a combination of elements.
 Minerals which are composed of more than one
element are bound together by chemical bonding.
All minerals formed by more than one element are
bound together by positive and negative ions.
(…Contd)

 Minerals are formed from various processes and
source materials.
 Their growth are controlled by various physic-
chemical conditions including the mass-balance,
role of fluids, temperature, pressure, depth or
other factors of the environment.

Classification of Minerals
 Of all the characters of minerals, the chemical
constitution is the most fundamental, and it
naturally takes an important position in any rational
system of classification.
 Initially, grouping of minerals have been attempted
according to their association in the field.
(…Contd)

 Then the diversity of elements was considered.
 The crystallographers and mineralogists compared
the salts that have similar crystalline structure and
classified the minerals.
 An economic classification was also brought
forward based on their utility point of view.
(…Contd)

 Later, a comprehensive classification was
proposed by arranging the minerals by the
important fundamental element present in them.
 These elements were considered in the order of
Mendeleev’s periodic table. By this method, the
ores of any one metal are kept together, while at
the same time little violence is done to
isomorphous groups.
(…Contd)

 The silicates are complex in composition and
form a very important a rock-forming group.
 They are best kept as a division by themselves.
Inside this great division, if the whole range of
the silicates is to be considered, the arrangement
adopted in “Dana's System of Mineralogy" was
found to be convenient.

The Structure of Classification
 In the field of Mineralogy, the organizational
structure created by James Dwight Dana, aptly
named as Dana’s System of Mineralogy is the
widely accepted classification system for the study
of minerals.
 Dana was the first person to classify minerals into
an arrangement by composition and structure.
(…Contd)

 The first five editions of A System of Mineralogy,
were published in 1837, 1844, 1850, 1854, and
1868, and were authored or revised by James
Dwight Dana.
 Minerals are first separated into classes by anion.
(…Contd)

 The main classes are Elements, Oxides, Halides,
Sulfides, Carbonates, Phosphates, and Silicates.
There are many subclasses still based on
composition.
 Smaller groups that are chemically similar are
often grouped together.

Chemical classification of minerals
The chemical classification of minerals broadly divides
them into the following ten classes:
1. Native elements, Native metals and Alloys,
Carbides, Silicides, Nitrides & Phosphides.
2. Sulfides, Sulfosalts, Sulfarsenates & Sulfantimonates
3. Halogenides, Oxyhalides & Hydroxyhalides.
(…Contd)

Chemical classification of minerals
4. Oxides and Hydroxides-Vanadates, Arsenites,
Antimonites, Bismuthites, Sulfites, Iodates
5. Carbonates and Nitrates
6. Borates
7. Sulfates, Selenates, Chromates, Molybdates,
8. Phosphates, Arsenates, Vanadates & Polyvanadates
9. Silicates
10. Organic Compounds.

Class : Native elements, Native metals and Alloys,
Carbides, Silicides, Nitrides, Phosphides
 The Native elements, as the name implies, are
minerals containing individual or combined
chemical elements.
 Native element minerals occur in nature in
uncombined form with a distinct mineral
structure.
(…Contd)

Class : Native elements, native metals and Alloys,
The elemental class includes four sub-classes as
Metals and inter-metallic elements,
Naturally occurring alloys,
Semi-metals and
Non-metals.
The Elements Class contains minerals that are
composed of more than one element. (…Contd)

Class : Native elements, native metals and Alloys,
 These Elements, by the chemical definition are
composed of all the same atoms; whereas
substances composed of two or more elements are
compounds.
 The Metals and their alloys and the Nonmetals
belong to this group. Metal alloys are minerals that
are composed of combinations of different metals in
one mineral.

Sub-class: Native Metals and Alloys
The native metals include the following:
 Aluminum Al
 Cadmium Cd
 Chromium Cr
 Copper Cu
 Gold Au
 Indium In
 Iridium (Ir, Os, Ru)
(…Contd)

Sub-class: Native metals and Alloys
 Iron Fe
 Lead Pb
 Mercury Hg
 Nickel Ni
 Palladium Pd
 Platinum Pt
 Rhodium (Rh, Pt)
 Silver Ag
 Tellurium Te
 Tin Sn
 Titanium Ti
 Zinc Zn.

Metallic Alloys
 Metal alloys are the combinations of metals.
Under this group, the following combination of
elements lead to the formation of various
minerals.
 The combination of Iron + Nickel is reflected in
the minerals like Kamacite alpha, Taenite beta -
and Tetrataenite.
(…Contd)

Metallic Alloys
 The combination of Copper + Zinc is reflected in the
minerals like Brass (Cu3 Zn2 ) and Danbaite (CuZn2 ).
 The combination of Copper + Zinc + Aluminum is
reflected in the minerals like Cupalite (Cu, Zn)Al.
 The combination of Copper + Mercury is reflected in
the minerals like Belendorffite (Cu7Hg6 ).
(…Contd)

Metallic Alloys
 The combination of Copper + Gold is reflected in
the minerals like Auricupride (Cu3Au).
 The combination of Gold + Copper is reflected in
the minerals like Tetra auricupride (AuCu).
 The combination of Gold+ Silver + Lead is reflected
in the minerals like Hunchunite (Au, Ag)2Pb.
(…Contd)

Metallic Alloys
 The combination of Iridium + iron is reflected in
the minerals like Chengdeite (Ir3Fe ).
 The combination of Silver + Mercury is reflected in
the minerals like Eugenite (Ag9Hg2).

Native Non-metals and Semi-metals
The Native Non-metals and Semi-metals include the
following.
1. Antimony (Sb)
2.Arsenic (As)
3.Bismuth (Bi)
4.Diamond (C)
5.Graphite (C)
(…Contd)

Native Non-metals and Semi-metals
6. Selenium (Se)
7. Silicon (Si)
8. Sulfur (S)
9. Tellurium (Te)
Minerals with metallic and non-metallic
elements include mostly Iron +
Nickel in combination with non-
metals like P, C, Si and N.

Class : Sulfides, Sulfosalts, Sulfarsenates,
Sulfantimonates
 The sulphide class includes four categories of
minerals as Sulfides, Sulfosalts, Sulfarsenates and
Sulfantimonates.
 A group of minerals that are compounds of one or
more metallic elements combined with the non-
metallic element Sulfur.
 The Sulfides also occur as economically important
class of minerals.
(…Contd)

 Most major ores of important metals such as
copper, lead and silver are all occurring as sulfide
minerals in nature.
 This family includes, minerals of Sulphides &
sulfosalts, Selenides, Telluride, Antimonide and
Arsenides.
Class : Sulfides, Sulfosalts, Sulfarsenates,
Sulfantimonates

The Standard Sulfides
 Sulfur ions (S2-
) bind with a number of positive ions to
form the sulfide minerals. Many of them are important
ores for the ions to which they bind.
 Antimony Sulfide occurring as Stibnite
 Arsenic Sulfide occurring as Orpiment and Realgar
 Bismuth Sulfide occurring as Bismuthinite
 Cadmium Sulfide occurring as Greenockite
 Cobalt Arsenic
Sulfide occurring as Cobaltite
(…Contd)

 Copper
Antimony Sulfide occurring as Famatinite
 Copper
Iron Sulfide occurring as Bornite, Chalcopyrite
and Cubanite
 Copper
Iron Tin Sulfide occurring as Stannite
 Copper Sulfide occurring as Chalcocite, Covellite
& Digenite
(…Contd)

 Iron Arsenic Sulfide occurring as Arsenopyrite
 Iron Nickel Sulfide occurring as Pentlandite
 Iron Sulfide occurring as Marcasite, Pyrite &
Pyrrhotite
 Lead Sulfide occurring as Galena
 Manganese Sulfide occurring as Alabandite
 Mercury Sulfide occurring as Cinnabar
(…Contd)

 Mercury Sulfide occurring as Meta-cinnabar
 Molybdenum Sulfide occurring as Molybdenite
 Nickel Sulfide occurring as Millerite &
Polydymite
 Silver
Germanium Sulfide occurring as Argyrodite
 Silver Iron Sulfide occurring as Argentopyrite
(…Contd)

 Silver Iron Sulfide occurring as Sternbergite
 Silver
Selenium Sulfide occurring as Aguilarite
 Silver Sulfide occurring as Argentite
 Tungsten Sulfide occurring as Tungstenite
 Vanadium Sulfide occurring as Patronite
 Zinc Iron Sulfide occurring as Sphalerite

Sulfosalts
 The sulfosalts are typical minerals occurring with the
combinations of copper, iron, lead, silver, arsenic,
bismuth, antimony and tin. The major minerals and their
composition are as follows:
 Chalcostibite containing Copper Antimony Sulfide
 Enargite containing Copper Arsenic Sulfide
 Emplectite containing Copper Bismuth Sulfide
 Berthierite containing Iron Antimony Sulfide
(…Contd)

Sulfosalts
 Cylindrite containing Iron Lead Tin
Antimony Sulfide
 Boulangerite containing Lead Antimony Sulfide
 Gratonite containing Lead Arsenic Sulfide
 Bournonite containing Lead Copper
Antimony Sulfide
 Aikinite containing Lead Copper
Bismuth Sulfide
(…Contd)

Sulfosalts
 Franckeite containing Lead Tin Iron
Antimony Sulfide
 Miargyrite containing Silver Antimony Sulfide
 Proustite containing Silver Arsenic Sulfide
 Matildite containing Silver Bismuth Sulfide
 Polybasite containing Silver Copper
Antimony Sulfide and
 Andorite containing Silver Lead
Antimony Sulfide.

Class : Halogenides, Oxyhalides & Hydroxyhalides
 This class includes Halogenides, Oxyhalides and
Hydroxyhalides. The Halides are a group of
minerals whose principle anions are halogens.
 Most of the halides are very soft and easily
dissolved in water. Halite and Fluorite are the well
known examples of this group.
 The halogens that are found commonly in nature
include Chlorine, Bromine, Iodine and Fluorine.(…Contd)

This group of minerals includes
a) Anhydrous Chlorides, Bromides, Iodides, and
Fluorides.
b) Oxychlorides and Oxyfluorides
c) Hydrous Chlorides and Hydrous Fluorides.
The common minerals of Anhydrous Halides include
Calomel – (horn quicksilver)- which Mercurous
Chloride.
Class : Halogenides, Oxyhalides & Hydroxyhalides

Halite group
Halite is commonly known as rock salt. It is the
mineral form of sodium chloride (Na Cl). The halite
group include the following minerals:
Halite- NaCl- the common Rock salt.
It is the salt which is used in our daily diet.
Sylvite- KCl- potassium chloride.
Sal Ammoniac- (NH4)Cl- ammonium chloride.
Villiaumite – NaF – sodium fluoride.

Fluorite group
Fluorite which is also called fluorspar, is a halide
mineral. It is composed of calcium fluoride, CaF2.
This group include the following minerals:
Fluorite ( Fluor spar)- Calcium Fluoride
Cryolite – Fluoride of Sodium and Aluminum

Oxychlorides and Oxyfluorides
 Oxychloride is a compound having oxygen and
chlorine atoms bonded to another element.
 This group includes the mineral Atacamite. It is a
Hydrated copper oxychloride.
 In addition, there are Hydrous Chlorides and
Hydrous Flurides.
(…Contd)

Oxychlorides and Oxyfluorides
The major minerals of these groups include
 Carnallite, which is a hydrated potassium
magnesium chloride and
Prosopite which is a hydrated calcium aluminum
fluoride.

Class : Oxides and Hydroxides
 The Class on Oxides and Hydroxides include a
wide variety of minerals belonging to Vanadates,
Arsenites, Antimonites, Bismuthites, Sulfites and
Iodates. Oxygen is the most abundant element
in the Earth's crust.
 It bonds readily with a number of metallic ions
to form the oxides. These oxides form important
ores for the metal resources.
(…Contd)

Class : Oxides and Hydroxides
 Most of the industrial minerals belong to this
group. Important minerals of the Oxide Group
are the following:
 Oxides of Silicon
 Oxides of semi-metals
 Oxides of metals and
 Intermediate oxides.

Oxides of Silicon
 Quartz is one the major mineral group present in
almost all rocks of the earth due to its abundance.
The major minerals are
 Quartz Group of minerals containing SiO2 as their
composition.
 Tridymite which is also a pure silica
 Opal which is a gem mineral containing Hydrous
Silicate
 And Amethyst which is a Purple quartz.

Oxides of Semi-metals
 Oxides of semi-metals are typical mineral groups.
 They include minerals like
 Arsenolite containing Arsenic Trioxide
 Valentinite containing antimony trioxide
 Tungstite containing Tungsten trioxide.

Oxides of metals
 The oxide mineral class includes those minerals in
which the oxide anion (O2-
) is bonded to one or
more metal ions. Cuprite is an oxide mineral
composed of copper oxide Cu2O, and is a minor
ore of copper. This is a major mineral belonging to
this group.
 There are two other groups of minerals belonging
to the oxides of metals.
 They are Periclase Group and hematite group.
(…Contd)

Oxides of metals
The minerals of these groups are as follows:
Periclase Group with
 Periclase containing Magnesia
 Manganosite containing Manganese protoxide
and
 Zincite containing Zinc Oxide.
(…Contd)

Oxides of metals
 Hematite Group with
 Corundum containing Al2O3
 Hematite containing Fe2O3 and
 Ilmenite containing (Fe, Mg )O. TiO2.
Corundum is one of the dominant Aluminum Oxide
belonging to this group. Corundum is the second
hardest natural mineral known to science.

Intermediate oxides
The intermediate oxides comprise of three major
mineral groups. They are spinel group, rutile group and
hydrous oxides.
 The Spinel group is comprised of Aluminum
Spinel called as Spinel
Iron Spinel which forms a group including Magnetite,
Jacobsite & Franklinite
Chromium Spinel forming Chromite and finally
Magnesium Aluminate.
(…Contd)

Intermediate oxides
 The Rutile group is comprised of four notable
minerals. They are:
 Cassiterite ( SnO2), Rutile ( TiO2)
 Octahedrite – Titanium dioxide and Pyrolusite
which is a Manganese dioxide.
 The Hydrous oxides group comprised of :
 Diaspore, Goethite, Manganite, Limonite, Bauxite,
Brucite, Gibbsite & Psilomelane.

Antimonides
 The minerals of this subclass include
 Gold Antimonite,
 Nickel Antimonite and
 Silver Antimonite.
 Aurostibite is a Gold Antimonide.

Arsenides
 The minerals of this subclass include
 Copper Arsenide,
 Nickel Arsenide, called as Nickeline,
 Cobalt Arsenide,
 Cobalt Nickel Arsenide called as Smaltite
 Platinum Arsenide and
 Cobalt Iron Arsenide called as Safflorite
 Iron arsenide called as Lollingite.

Class : Carbonates and Nitrates
 Carbonates and nitrates are very separate classes
of minerals. The carbonate ion can bond with a
variety of other ions to produce the carbonate
minerals.
 The bonding with calcium to form the mineral
calcite produces one of the most abundant of the
non-silicate minerals.
 All carbonates have the property of dissolving
easily in acidic water.
(…Contd)

Class : Carbonates and Nitrates
 Carbonates are further classified into two major
classes as anhydrous Carbonates and Basic-
hydrous carbonates.
 The Anhydrous Carbonates includes two groups
as Calcite Group and Aragonite Group of
Minerals.

Calcite Group
 The calcite group includes a variety of minerals with
varying chemical composition.
 The notable minerals are :
 Calcite which consists of Calcium carbonate.
 Dolomite - which consists of Calcium Magnesium
Carbonate.
 Ankerite- which consists Calcium Magnesium Iron
Carbonate.
 Magnesite- which consists of Magnesium Carbonate.
(…Contd)

Calcite Group
 Siderite- which consists of Iron Carbonate
 Rhodochrosite- which consists of Manganse
Carbonate
 Smithsonite- which consists of Zinc Carbonate
 Spaerocobaltite- which consists of Cobalt
Carbonate.

Aragonite Group
 The aragonite group includes the following
minerals:
 Aragonite - which consists of Calcium carbonate.
 Bromlite - which consists of Calcium Barium
Carbonate.
 Strontianite - which consists of Strontium
Carbonate.
 Cerussite - which consists of Lead Carbonate.

Basic and Hydrous carbonate
The basic and hydrous carbonates are yet another
group of minerals. The minerals of this group are:
 Malachite – which consists of Basic cupric hydrous
carbonate and
 Azurite - which consists of Basic cupric hydrous
carbonate.

Nitrates
 Nitrates are soluble minerals. These minerals are few
in number and with the exception of soda niter are
of rare occurrence.
 Nitrates are similar to carbonates.
 Niter, specifically KNO3, is also known as
"saltpeter".
 Nitrate Minerals include Sodium Nitrate, Calcium
Nitrate, Barium Nitrate, Niter, and Nitratine.
(…Contd)

The Normal anhydrous and hydrated nitrates
occurring as minerals are:
 soda niter, NaNO3;
 niter, KNO3:
 ammonia niter, NH4NO3;
 nitrobarite, Ba(NO3)2;
 nitrocalcite, Ca(NO3)2 · 4H2O; and
 nitromagnesite, Mg(NO3)2 · 6H2O.
Nitrates
(…Contd)

 The natural nitrates are for the most part readily
soluble in water.
 Niter is one of the few nitrate minerals that is
available on the mineral markets.
 In fact, some solid nitrate crystals will even become
liquid by removing water from the moisture in the air,
a process called deliquescence.
Nitrates

Class : Borates
 Borates are separate classes of minerals. Borate is a
compound of the borate ion with metallic elements.
 The Borate minerals are more complex in their
structures than typical carbonates.
 It is because of the scarcity and limited distribution of
boron in the Earth's crust.
 There are more than 100 different borate minerals
occurring in nature.
(…Contd)

The most common Borate Minerals are the following:
 Kernite - Na2B4O7.4H2O; Kernite is a sodium borate
hydrate
 Borax - Na2B4O7.10H2O; Borax is a sodium borate
hydrate.
 Ulexite - NaCaB5O9.8H2O; Ulexite is a sodium calcium
borate hydrate
 Colemanite - Ca2B5O11.5H2O; Colemanite is a calcium
borate hydrate,
Class : Borates
(…Contd)

 Boracite Mg3B7O13Cl; Boracite is a Magnesium
Borate Chloride
 Sussexite- HRBO3; Sussexite is the Magnesium
Borate Hydroxide
 Hydroboracite Hydroboracite is the Hydrated
Calcium Magnesium Borate
Hydroxide.
Class : Borates

Class: Sulfates, Selenates, Chromates, Molybdates,
 This Class includes many minerals belonging to Sulfates,
Selenates, Chromates, Molybdates, Wolframates and
Niobates.
 The Sulfates are an important mineral class and include
some very interesting and attractive specimens.
Although many minerals belong to this class, only
barite, gypsum, Celestite, and anhydrite can be
considered common.

Selenides
The minerals of the selenide subclass include
a) Copper Selenide,
b) Lead Selenide,
c) Silver Copper Selenide and
d) Mercury Selenide.

Tellurides
The minerals of the telluride subclass include

Notable telluride minerals are:
 (Silver Gold Telluride)
 Melonite (Nickel Telluride)
 Cala erite (Gold Telluride)
 Empressite (Silver Telluride)
 Petzite (Silver Gold Telluride)

Class: Phosphates, Arsenates, Vanadates &
Polyvanadates
 This Class includes minerals belonging to Phosphates,
Arsenates, Vanadates and Polyvanadates.
 Phosphorous in the form of phosphate ions (PO4
3-
)
binds with positive ions to form the phosphate
minerals.

Phosphates
 The Important minerals of phosphates are

Class : Silicates
 The Class on silicate includes a vast number of
minerals belonging to the Silicates family.
 The Silicates are the largest, the most interesting,
and the most complicated classes of minerals.
 Approximately, 30% of all minerals present on the
earth are silicates.
(…Contd)

 Some geologists estimate that about 90% of the
Earth's crust is made up of mainly silicates.
 Oxygen and silicon are the two most abundant
elements in the earth's crust.
 Because of this the abundance of silicates is seen.
 The basic chemical unit of silicates is the Si O4
tetrahedron.
Class : Silicates
(…Contd)

 The Silicate tetrahedrons have more complicated
structures.
 The silicate tetrahedrons combine each other and
make the typical Silicate Class.
 They are the rock-forming silicates.
Class : Silicates

Classification of silicates
The Silicates are divided into the following six subclasses,
not by their chemistries, but based on their structures:
Nesosilicates (single tetrahedrons)
Sorosilicates (double tetrahedrons)
Inosilicates (single and double chains)
Cyclosilicates (rings)
Phyllosilicates (sheets)
Tectoilicates (frameworks).

 The Nesosilicates are called as single tetrahedron
silicates. These are also called as orthosilicates.
 They have an independent Si-O tetrahedral structure.
 These form separate groups of minerals.
Nesosilicates
(…Contd)

The major groups of minerals are
 Olivine group,
 Garnet group,
 Zircon group,
 Alumino-silicate group,
 Humite group,
 Titanite and chloritoid group of minerals.
Nesosilicates
(…Contd)

 The Olivine group includes major minerals like
Forsterite and Fayalite.
 The Garnet group of minerals include Pyrope,
Almandine, Spessartine, Grossular, Andradite &
Uvarovite minerals.
 The Zircon group includes Zircon and Thorite.
Nesosilicates
(…Contd)

The Alumino-silicate group includes
 Andalustie
 Kyanite
 Sillimanite
 Topaz and
 Staurolite minerals.
The Humite group include Chondrodite and Humite.
Nesosilicates

 Sorosilicates are double tetrahedrons silicates. They
posses two linked Si-O tetrahedra sharing one
oxygen.
 They include epidote group of minerals as major
groups. The notable ones are the epidote and
vesuvianite groups. The Epidote group includes
major minerals like Epidote, Zoisite and Allanite.
 The Vesuvinite group includes indocrase minerals.
Sorosilicates (double tetrahedrons)

 The Inosilicates occur as single and double chain
structure of silicates.
 The most important mineral groups of Inosilicates
are the pyroxenes and the amphiboles.
 Pyroxenes are the most important rock forming
ferromagnesian silicate minerals.
 They occur in almost every type of igneous rocks.
Inosilicates (single and double chains)
(…Contd)

 These single-chain Inosilicates include the following
mineral groups:-
 The Pyroxene group includes minerals like Enstatite
& Ferrosilite, Diopside & Augite, Jadeite, Ageirine
(Acmite) & Sodumene.
 The Pyroxenoid group includes minerals like
Wollastonie, Rhodonite & Pectolite.
(…Contd)

 The pyroxenes can be further divided into two more
groups based on chemistry and crystallography.
 The first one is the Orthorhombic Pyroxenes,
Orthopyroxenes in short, which includes enstatite -
MgSiO3 and ferrosilite - FeSiO3 and the second one is
the Monoclinic Pyroxenes, Clinopyroxenes in short,
which includes Diopside- Hedenbergite series.
(…Contd)

 In addition, we have the Sodic Pyroxenes
comprising minerals like Jadeite (NaAlSi2O6) and
Aegerine (NaFe+3
Si2O6), Augite and Pigeonite.

 These silicates show continuous chains of Si-O
tetrahedra, sharing two oxygens. The amphibole
group of minerals are double chain silicates, for
example the tremolite - ferroactinolite series.
Double chain inosilicates
(…Contd)

 The Amphibole group of minerals include
Anthophyllite, Cumingtonite series, Tremolite,
Actinolite, and Hornoblende. It also includes
Sodium amphibole minerals.
Double chain inosilicates

 The Cyclosilicates show closed rings of linked Si-O
tetrahedral, sharing two oxygens.
 The most common minerals based on this structure
are Beryl, Cordierite, dioptase and Tourmaline.
Cyclosilicates (rings)

 The Phyllosilicates are called as sheets silicates. These
silicates show continuous sheets of Si-O tetrahedra
sharing three oxygens.
 Many members of this class have a platy or flaky habit
with one very prominent cleavage.
 Minerals are generally soft, low specific gravity, may
even be flexible. Mostly hydroxyl-bearing minerals.
Phyllosilicates(sheets)

The phyllosilicates are an important group of minerals that
includes the micas, chlorite, serpentine, talc, and the clay
minerals. The major mineral groups are:
Serpentine group
Clay mineral group with Kaolinite, Illite & Montmorillonite
Vermiculite & Talc
Mica group including Biotite, Muscovite & Phlogopite and
Chlorite group with Chlorite.
Phyllosilicates(sheets)

 The micas can be divided into the dioctahedral micas
and the trioctahedral micas. Muscovite, Paragonite, and
Margarite are the white micas, and represent the
dioctahedral group.
 Biotite and Clintonite (Xanthophyllite) are the black or
brown micas representing the tri-octahedral group.
 Muscovite and Biotite are the most common micas.
The Micas

 The Tectosilicates show continuous framework of
Si-O tetrahedra sharing all four oxygens.
 All oxygen atoms are shared between two SiO4
tetrahedron.
 Quartz group with Quartz, Tridymite and
Cristobalite belong to this class.
Tectosilicates (frameworks)

 In addition, the feldspar and feldspathoid minerals are
also based on the tectosilicate framework. These
silicates include the following groups of silicates:
 Feldspar family with Alkali-feldspars and Plagioclase
feldspars
 Fildspathoid family with Nepheline and Sodalite
 Sacpolie group
 Zeolite group with Natrolite, Chabazite & Heulandite.
(…Contd)

 The structure of feldspar is similar to that of the
SiO2 polymorphs, consisting of an infinite network
of tetrahedral, inter-connected via bridging oxygen
atoms.
 Among these, the Feldspars are the most common
rock-forming minerals.

 This class includes those organic compounds that are
recognized and classified as minerals.
 Organic minerals are essential items which bring life
to cells. These contain carbon, and their electrons
spin clockwise, just like those of the human body.
 In fact, the body needs about 70 different minerals to
carry out all the functions a body is required to do.
Class: Organic Compounds
(…Contd)

The Organic Minerals include the following:
 Salts of Organic Acids (Oxalates)
 Salts of Organic Acids (Mellitates, Citrates,
Cyanates, and Acetates)
 Salts of Organic Acids (Hydrocarbons)
 Salts of Organic Acids with miscellaneous
formulae.
Class: Organic Compounds

 Mineralogy is a vast subject. More than 3000 minerals
have been recognized so far.
 It is necessary to know the details about these
minerals, their chemical formula, physical and
chemical properties and the way in which they are
used in different industries.
Conclusion
(…Contd)

 Systematic mineralogy is the subject which divides
these minerals into different classes based on their
chemical formulas. Many mineral collectors, collect
or categorize their collections mainly based the
mineral classes only.
 The chemical classification of minerals give an overall
structure and composition of the minerals of the
world.
Conclusion

Classification of minerals

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