Mineralogy

References :

-Mineralogy ---- Author, Berry

-Manual of Mineralogy --- Author , Dana

First Graders 2nd course 2019/2020

What are the Mineral properties

• Mineral is naturally occurring

• Homogeneous

• Solid

• Inorganically formed

• Definite chemical composition and /or ordered atomic arrangements (Crystal form).

• NaCl

• Definite chemical composition and ordered atomic arrangement

• If one of the atoms lost, deformity will appears

In to the structure systems , so that the mineral to

lose it is properties . Example : Glass

Na

Cl

Na

Cl

Na

Cl

Na

Cl

Na

(Nomenclature)Naming of Minerals

• The names of some minerals are very old and their origins are lost.

Exp.: Zircon (ZrSiO4) in to the Persian language meaning ( Zar con )

• Many names are derived from Greek or Latin words that give some information's about the physical aspects of minerals.

Exp.: Color ……. Albite ---------- Albus

Crystal Form …… Phyllite --------- Phyllon

Density ……… Barite -------- Bary ( Heavy)

• Many Minerals Derived from the chemical composition .

Exp.: Calcite-------- CaCO3

• Many Minerals derived from location that first Discovered .

Exp.: Muscovite -------- Moscow ,

Iranite, Iraqite, Baghdadite, Qandelite

• Dana Sugest any name ended with (ite) , mining minerals.

Subfields of Mineralogy

• Descriptive Mineralogy – documenting physical and optical properties

• Crystal Chemistry – relationship of chemical composition to atomic structure

• Crystallography – relationship of crystal symmetry and form to atomic structure

• Mineral Genesis – interpreting the geologic setting in which a mineral forms from its physical, chemical, and structural attributes and its associated minerals

Definition A mineral is a naturally occurring solid with a highly ordered atomic arrangement and a definite (but not fixed) chemical composition. It is usually formed by

inorganic processes

• What are the methods to study minerals

1. Study the Crystal structure of Minerals

2. Study the Natural (Physical) properties of minerals

3. Study the chemical properties of minerals.

4. Study the mineral deposits .

5. Quality study of minerals.

6. Optical study of minerals.

Fundamental Position of Mineralogy to all other Earth Science Disciplines

• Petrology – the study of the origin of rocks is largely determined by evaluating the structure, texture, and chemistry of the minerals they contain.

• Geochemistry – study of the chemistry of earth materials which reflects the collective chemistry of the minerals they contain

• Structural Geology and Tectonics – Deformation of rocks is controlled by the orientation and crystal structure of its constituent minerals

• Environmental Geology/Hydrogeology – the study of how the biosphere, hydrosphere, and atmosphere interacts with rock and minerals (the lithosphere).

• Economic Geology – study of the origin and beneficiation of mineral deposits

Origin and forming methods of minerals in to the natures

1. From Magma or Lava

2. From surface solution

3. From Metamorphism processes

Classification of Minerals

According to: 1. Crystal chemistry Classification

There are some minerals owner different chemical structure, but they have same crystal forms. And their approach results from look like in to the inner atomic arrangement.

2. Economic Chemical Classification

This classification depending on economical estimate from major elements.

3. Chemical Classification

It has an important methods for mineral classification.

Exp. : oxides , carbonate, sulfide, phosphate ….

Non crystalline minerals (Amorphous minerals)

1- Mineralloid a) Originally form from magma or of the other environments due

to 1. raped cooling or crystalline from 2. gelatins material b) Alteration from original crystal minerals exp.: Hematite Fe2O3,

Magnetite Fe3O4 -------- Geothite FeO.OH , Limonite FeO(OH) · nH2O , when H2O occurs 2- Metamict minerals : Which originally formed as crystalline compounds and in which the crystalline structure has latter been destroyed by radioactive materials (U,Th) that emitted 𝛼, 𝛽, Y particles (Those minerals originally have lost the crystallinity due to radiation ) exmp.: Zircon (ZrSiO4) Zr +4 ------------- Hf (non- radioactive ), Th, U (radioactive)

• Isomorphism :

is a group of minerals having same crystal structures (forms) and different chemical composition. Exp. Aragonite group orthorhombic Aragonite CaCO3

Witherite BaCO3

Strontianite SrCO3

Cerrussite PbCO3 • They have the same crystal system

(Orthorhombic), but differs in chemical composition

• Note. If the chemical composition changed, is required to change the name of the Mineral. Calcite Group: trigonal

• Calcite CaCO3 • Siderite FeCO3 • Rhodochrosite MnCO3 • Smithsonite ZnCO3 • Magnesite MgCO3 • Polymorphism: Is a group of mineral having same chemical composition and different crystal form. Exp.: Calcite ---- CaCO3 ----- Triginal Aragonite ------ CaCO3 ---- Orthorhombic SiO2 Low Quartz -------------- Trigonal High Quartz -------------- Hexagonal Tridymite ----------Hexagonal Cristobalite --------- Cubic Coesite ----- Monoclinic Stishovite --- Tetragonal

• Pseudomorphism : Mineral can be replaced by another minerals without any change in external form. The later minerals have been formed the original by chemical alteration and may originate by

1. The loss of a constituent (Native Cu after azurite Cu

Co3.Cu(OH)2 )

2. The gain of a constituent ( Gypsum after Anhydrite) .

3. Partial exchange of constituents (Goethite after Pyrite) .

4. Complete exchange of constituents (Quartz after fluorite).

Paramorphism :

Is term used when one polymorph changes to another without change in external form.

Solid Solution : two minerals are interfere with each other because of substitution of elements that have same ionic radius and charge

Ex Solution : The term ex refers to process whereby an initially homogeneous solid solution separates in to two distinct crystalline mineral without the addition or removal of material. Luminescence : Any emission of light by a mineral du to foreign ions called activators. Theromluminescence : emitting visible light when it heated to a temperature below that of red heat . Piezoelectricity : forming electrical charge when the mineral effect to pressure. Pyroelectricity : It is phenomena that induce electrical charge by change in temperature

• THE GENESIS OF MINERALS

- The magmatic Environments.

Magma is essentially a hot silicate melt and is the parent material of igneous rocks. (volcanic, plutonic) ,

Igneous rock are the product of crystallization of magma. The mineralogy of igneous rocks is comparatively simple only seven minerals group (essential constituents) Quartz, Feldspars, Feldspathoids, Pyroxenes, Hornblends, Biotite and Olivine .

A number of other minerals may be present in small amounts (accessory constituents) such as Magnetite, Ilminite, Apatite, Muscovite, Sphene, Zircon, Fluorite, Pyrite,

* Leucocratic (light – colored minerals)--- ( SiO2 Minerals, Feldspar,

Feldspathoids).

* Melanocratic (dark colored minerals) ----- (Olivine, Pyroxene , Hornblende, Biotite).

All of these minerals are never present in single igneous rock.

• Magmatic Crystallization:

• The silicate minerals crystallizing from magma

• Pegmatite :

Chemical and geological evidence indicates that the residual melt from the fractional crystallization of magma will generally be a siliceous liquid rich in alkalis and containing water and other volatiles. And with concentration of these miner elements in the structure of common minerals.

• Hydrothermal minerals: Hydrothermal deposit, represent a later development than pegmatite being formed from cooler and more dilute solution (rich in H2O and gass)

There type

• Hypothermal 300 -500

Cassiterite, scheelite, wolframite

• Methothermal 200 -300

Siderite, rhodochrosite, sphalerite

• Epithermal 50 – 200

Stibnite, mercury , cinnabar , opal

• Pheumatolytic stage:

In this stage the concentration of gases increase these gas are chemically active and react with other constituent to form special mineral

4F + Sn SnF4

SnF4 + 2H2O SnO2 + 4HF

4HF + 2CaCO3 2CaF2 +2H2O+2CO2

Cassterite

• Sedimentary Environment

Sedimentation is the result of interaction of atmosphere and hydrosphere on the crust of the earth.

The constituent of crust are igneous rocks these rocks are formed under high Temperature and pressure and they cannot be expected to remain stable under the very different condition at the earth surface.

The behavior of chemical element during sedimentary processes has been found to depend largely on relationship between ionic size and ionic charge.

• The factor charge / Ionic radius is known Ionic potential