[PPT] - so lid solid and inorganic representable by a chemical formula, and PowerPoint Presentation

SLIDE 1

3/25/2015 1

De finitio n & T ype s o f Mine ra l

I mag e so urc e : http://www.c ario nmine raux.c o m/mine raux/Mine raux_Juille t_ao ut_2008/q uartz_ve rt_c hine _1.jpg

W. K

a nitpa nya c ha ro e n

Learning goals 1.Understand the definition of mineral 2.Distinguish differences between mineral and non‐ mineral substances 3.Understand different types of silicate minerals 4.Learn about Nesosilicates, particularly olivine and garnet, and remember their physical characteristics

2. Na tura lly

i

1. I

no rg a nic

so lid

De finitio n

c c urring
3. De finite

c he mic a l

c o mpo sitio n

I mag e so urc e : http://www.c ario nmine raux.c o m/mine raux/Mine raux_Juille t_ao ut_2008/q uartz_ve rt_c hine _1.jpg

4. Orde re d

a to mic

a rra ng e me nt

Mineral is a naturally occurring substance that is

solid and inorganic representable by a chemical formula, and has an ordered atomic structure. It is different from a rock, which can be an aggregate f i l i l d d t h

f minerals or non‐minerals and does not have a

specific chemical composition.

SLIDE 2

3/25/2015 2

I s sa lt a mine ra l?

I mag e so urc e : http://www.te atro naturale .it/me dia/img /c ib o /2014/S alt-014.jpg

Ye s: Ha lite (Na Cl)

Salt also known as sodium chloride or halite is an

ionic compound with the chemical formula NaCl. This mineral can be easily found in our daily lives such as in food, preservatives, and industrial processes.

I mag e so urc e : https://pe da.ne t/o ppimate riaalit/e -o ppi/lukio /n%C3%A4yte luvut/e ke 2/41/ke rtaus/4-2-io nisido s/nac l- kide rake nne :file /do wnlo ad/8b b e e b 2c 420e 44e b 40b b d450b a4b 80f2e 45d0347/nac l-kide rake nne .jpg

F a c e -Ce nte re d Cub ic (F CC)

In solid sodium chloride, each ion is surrounded by

six ions of the opposite charge as expected on electrostatic grounds. The surrounding ions are located at the vertices of a regular octahedron. The larger Cl ions (green) are arranged in a cubic array g (g ) g y whereas the smaller Na ions (yellow) fill all the cubic gaps (octahedral voids) between them. This same basic structure is found in many other minerals and is commonly known as the rock‐salt crystal structure.

It can be represented as a face‐centered cubic (fcc)

lattice with a two‐atom basis or as two interpenetrating face centered cubic lattices. The first atom is located at each lattice point, and the second atom is located half way between lattice points along the fcc unit cell edge.

SLIDE 3

3/25/2015 3

I s sno wfla ke a mine ra l?

I mag e so urc e : http://www.wallpape rsdb .o rg /wallpape rs/ho lidays/sno wflake _c lo se _1920x1200.jpg

Ye s: H

2O

I mag e so urc e : http://wallpape rswide .c o m/sno wflake -wallpape rs.html

A snowflake starts forming when a tiny dust or

pollen particle comes into contact with water vapor high in Earth's atmosphere. The water vapor coats the tiny particle and freezes into a tiny crystal of ice. Thi ti t l ill b th " d" f hi h This tiny crystal will be the "seed" from which a snowflake will grow. Snowflake is thus mineral because it is naturally occurring solid with a definite chemical composition and an ordered internal structure.

However an ice cube made in a refrigerator would

However an ice cube made in a refrigerator would not be considered a mineral because it was produced by the actions of people. L iq uid H

2O

fre e ze

I mag e so urc e : http://www.e astte nne sse e wildflo we rs.c o m/imag e s/S no wflake _mo le c ule s.jpg

So lid H

2O

Na tura lly o c c urre d

g ro w

Snowflakes always have 6 sides because when water

molecules freeze they form a 6‐sided ring (hexagon). As more molecules freeze, the snowflake becomes a 6‐pointed crystal. The newly‐formed ice crystal ( fl k ) i h i th th di i d it (snowflake) is heavier than the surrounding air and it begins falling.

As it falls towards Earth through humid air more

water vapor freezes onto the surface of the tiny

crystal. The snowflake grows larger and larger as it

falls enlarging the hexagonal pattern falls, enlarging the hexagonal pattern.

SLIDE 4

3/25/2015 4

Just like o the r mine ra ls, sno wfla ke s ha ve ma ny struc ture s!

I mag e so urc e : http://www.e arthzine .o rg /wp-c o nte nt/uplo ads/2012/07/I mag e -o f-diffe re nt-type s-o f-sno w-flake s.jpg

Although all snowflakes have a hexagonal shape
ther details of their geometry can vary. These

variations are produced by different temperature and humidity conditions through which the fl k f ll snowflake falls.

Some temperature/humidity combinations produce

flakes with long needle‐like arms. Other conditions produce flakes with wide flat arms. Other conditions produce thin, branching arms.

I s sug a r a mine ra l?

I mag e so urc e : http://www.o asisdisc ussio ns.c a/wp-c o nte nt/uplo ads/2014/03/b ig sto c k-S e ve ral-type s-o f-white -sug ar-41900299.jpg 4.jp g

No : C 12H

22O 11

Sugar can form crystals, but since sugar is composed
f organic material, these crystals are not minerals.

Minerals have to be naturally created or else they are classified as man‐made substances.

SLIDE 5

3/25/2015 5

Sug a r fo rms c rysta l b ut it’ s or

ganic !

I mag e so urc e : http://s.hswstatic .c o m/g if/fo o d-g luc o se .g if

Sugar forms crystal but it’s organic!

How many mine ra ls a re o ut the re ?

a . 400 b . 4,000 40 000 c . 40,000

d. 400,000

I mag e so urc e http://me dia.ido wnlo adblo g .c o m/wp-c o nte nt/uplo ads/2014/06/Yo se mite .jpg

There are approximately 3800 known minerals.

About 30 to 50 new minerals are described and one

r two minerals are discredited each year. The most

complete listing of minerals is J. Mandarino Fl i h ' Gl f Mi l S i 1999 Fleischer's Glossary of Mineral Species 1999 published by the Mineralogical Record.

SLIDE 6

3/25/2015 6

T ype

b ase d o n atomic ar r ange me nt

I mag e so urc e : http://uplo ad.wikime dia.o rg /wikipe dia/c o mmo ns/thumb /0/05/Crystalline _po lyc rystalline _amo rpho us2.svg /2000px-Crysta lline _po lyc rystalline _amo rpho us2.svg .png

Amo rpho us

e .g . g la ss, o pa l (SiO 2)

Crysta lline

e .g . q ua rtz (SiO 2)

Crystalline solids have regular ordered 3D arrays of

components held together by uniform intermolecular forces, whereas the components of Amorphous solids are not arranged in regular (f th G k á h i

arrays. (from the Greek ámorphos, meaning

“shapeless”).

T ype

b ase d o n c he mic al c omposition

Silic a te s

Must c o nta in Si a nd O e .g . Ortho c a lse (K AlSi3O 8)

I mag e so urc e http://www.kidzro c ks.c o m/v/vspfile s/pho to s/kidzkit-Calc ite -Rho mb -2.jpg ; http://www.g e msto ne b uzz.c o m/file s/g e msto ne / fe ldspar.jpg

No n-silic a te s

e .g . Ca lc ite (Ca CO 3)

Minerals can be categorized into 2 groups based on

their chemical composition.

1. Silicate minerals

The most common mineral group on Earth is the silicate minerals, which all have the elements silica and oxygen as their main ingredients. Most silicates form when molten rock cools, either at or near the Earth's surface or deep underground e.g. Orthoclase 2 N ili t i l

2. Non‐silicate minerals

Some of non‐silicates form when magma cools, while

thers form when water evaporates away leaving

mineral crystals behind e.g. Calcite , or when other minerals decompose.

SLIDE 7

3/25/2015 7

T he Six Silic a te s (SiO 4)4-

T e tra he dro n

Silic o n

Side vie w

I mag e so urc e http://www.thiso lde arth.ne t/I mag e s/silic ate _struc ture s.jpg

Silic o n Oxyg e n

T

p vie w
The basic chemical unit of silicates is the (SiO4)

tetrahedron shaped anionic group with a negative four charge (‐4). They can form as single units, double units, chains, sheets, rings and framework t t structures.

Ne sosilic a te s

r Ortho silic a te s

Isla nd

Sing le te trahe dro n

Si : O

1: 4

Bo w tie

2 : 7

T he Six Silic a te s

Sor

silic a te s

Bo w tie

Do ub le te trahe dro n

2 : 7

Cyc losilic a te s

Ring

1 : 3

Inosilic a te s

Cha in

Sing le o r Do ub le

4 : 11

I mag e so urc e http://www.thiso lde arth.ne t/I mag e s/silic ate _struc ture s.jpg

g

Phyllosilic a te s

She e t

2 : 5

T e c tosilic a te s

F ra me wo rk

1 : 2

The Silicates are divided into 6 groups, not by their

chemistries, but by their structures:

1. Nesosilicates (single tetrahedrons)
2. Sorosilicates (double tetrahedrons)
3. Inosilicates (single and double chains)
4. Cyclosilicates (rings)
5. Phyllosilicates (sheets)
6. Tectosilicates (frameworks)

SLIDE 8

3/25/2015 8

Ne so silic a te s

“I sland”

I mag e so urc e http://www.thiso lde arth.ne t/I mag e s/silic ate _struc ture s.jpg

One o f the mo st a b unda nt mine ra l o n

E a rth (surfa c e , ma ntle )

Olivine (Mg ,F e )2SiO 4

E a rth (surfa c e , ma ntle )

Mo stly o c c urre d in ma fic -ultra ma fic

ig ne o us (e .g . b a sa lt, g a b b ro , dunite , e tc ) & so me me ta mo rphic ro c ks

I mag e so urc e http:// http://www.impro ntaunika.it/wp-c o nte nt/uplo ads/2014/12/L

livina-dalla-c ristallo te rapia-alla-riduzio ne -de i-g as-se rra.jpg
Olivine is a common mineral in the Earth's

subsurface but weathers quickly on the surface. The ratio of magnesium and iron varies between the two end‐members of the solid solution series:

Forsterite (Mg‐endmember: Mg2SiO4) and
Fayalite(Fe‐endmember: Fe2SiO4).
Olivine is very common as a primary crystallization

product in Fe‐ and Mg‐rich magmas. Intermediate Fe‐Mg composition olivine is found in gabbro, basalt, peridotite, pyroxenite, and is the main component of

dunite. Fe‐rich olivine is found in syenites,

phonolites, trachytes, andesites, and dacites.

SLIDE 9

3/25/2015 9

Olivine

I mag e so urc e http://www.hawaiipic ture s.c o m/pic ture s/wallpape rs/g re e n-sand-b e ac h.jpg

“Papako le a” Gre e n sand b e ac h, Hawaii

Cinde r c o ne

E ro sio n b y se a wa te r se a wa te r Ba sa lt: ma fic o r fe lsic ?

I mag e so urc e http://i.img ur.c o m/ lypQ81V.jpg

SLIDE 10

3/25/2015 10

Olivine

T

wo e nd-me mb e rs in so lid so lutio n:

F a ya llite : F e 2SiO 4 F

rste rite : Mg 2SiO 4

g 2

4

I mag e so urc e http://www.zac ktrave l.c o m/wp-c o nte nt/uplo ads/2013/05/papako le a_b e ac h_hawaii_6.jpg

Also fo und in me te o rite s, mo o n, ma rs

Olivine (Mg ,F e )2SiO 4

Also fo und in me te o rite s, mo o n, ma rs L una r Olivine Ba sa lt 15555 Co lle c te d b y Apo llo 15

Ma re b a sa lts fro m the Imb rium Ba sin ra ng e fro m 3.4-3.4 b illio n ye a rs in a g e

I mag e so urc e http://uplo ad.wikime dia.o rg /wikipe dia/c o mmo ns/2/29/L unar_Olivine _Basalt_15555_fro m_Apo llo _15_in_Natio nal_Muse um_o f_Natural_Histo ry.jpg

Mg‐rich olivine has also been discovered

in meteorites, the Moon, Mars,

SLIDE 11

3/25/2015 11

1st mine ra l in the Bo we n’ s se rie s

(e a sily we a the re d)

Olivine (Mg ,F e )2SiO 4

(e a sily we a the re d)

Symme try: Ortho rho mb ic
Cle a va g e : Po o r
F

ra c ture : Co nc ho ida l

Ha rdne ss: 6-7
Ge msto ne : Pe rido t

I mag e so urc e http://uplo ad.wikime dia.o rg /wikipe dia/c o mmo ns/9/94/F

rste rite -Olivine -4jg 54a.jpg
Olivine gemstones are called peridot and chrysolite.

F e 2+ Mg 2+ SiO 4

4-

T

p-vie w

SiO 4

4-

Bo tto m-vie w

Ortho rho mb ic

Olivine's crystal structure incorporates aspects of

the orthorhombic P Bravais lattice, which arise from each silica (SiO4) unit being joined by metal divalent cations with each oxygen in SiO4 bound to 3 metal i Th th di ti t it ( k d

ions. There are three distinct oxygen sites (marked

O1, O2 and O3 in figure 1), two distinct metal sites (M1 and M2) and only one distinct silicon site. O1, O2, M2 and Si all lie on mirror planes, while M1 exists on an inversion center. O3 lies in a general position. position.

SLIDE 12

3/25/2015 12

F

r

se te r ite

Mg 2SiO 4

F ayallite

F e 2SiO 4

I mag e so urc e http://2.b p.b lo g spo t.c o m/-idk52L c O0g 8/UuGe juJvmT I /AAAAAAAABGQ/t8jZ a48R6Z E /s1600/%D1%81%D0%B1%D0%BE %D1%80%D0%BA%D0%B0.jpg

L a rnite Ca 2SiO 4 Mo ntic e llite CaMgSiO 4 K irsc hte inite CaF e SiO 4 C l t lid F a ya lite F e 2SiO 4 F

rse te rite

Mg 2SiO 4 0 10

20 30 40 50 60 70 80 90 100

v v v v v v v v v

Co mple te so lid so lutio n se rie s

Co mpo sitio n (Mo le c ula r %)

Mo difie d fro m http://me dia-1.we b .b ritannic a.c o m/e b -me dia/68/2668-004-D6ADA523.jpg

(Mg 0.8F e 0.2)2SiO 4 (Mg 0.05F e 0.95)2SiO 4

Compositions of olivine are commonly expressed as

molar percentages of forsterite (Fo) and fayalite (Fa) (e.g., Fo70Fa30).

SLIDE 13

3/25/2015 13

ºC) 1890 -

L iq uid

L iq uidus line

1700 -

At T

1 (1890 ºC)

All liq uid
Co mpo sitio n:

Mg 50% F e 50% At T

2 (1700 ºC)

Mo stly liq uid &

so me so lid

Co mpo sitio n:

Mg 50% Mg 80%

T

1

T

2

T e mpe ra ture (º 1700

Mg 50% Mg 80% F e 50% F e 20% (L iq uid) (So lid) At T

3 (1575 ºC)

L

iq uid & so lid

Co mpo sitio n:

Mg 30% Mg 65% F e 70% F e 35% (L iq uid) (So lid)

1575 - 1450 -

At T

4 (1450 ºC)

i

T

2

T

4

T

3

F

rse te rite

Mg 2SiO 4 F a ya lite F e 2SiO 4

Co mpo sitio n(%) 1205 -

Mo difie d fro m http://ijo lite .g e o lo g y.uiuc .e du/08S prg Class/g e o 436/imag e s/Olivine .jpg

0 10 20 30 40 50 60 70 80 90 100

So lid

So lidus line

Mo stly so lid &

so me liq uid

Co mpo sitio n:

Mg 18% Mg 50% F e 82% F e 50% (L iq uid) (So lid)

Binary solid solutions: Forsterite has a high melting

temperature at atmospheric pressure, almost 1900 °C, but the melting temperature of Fayallite is much lower (~1200 C). The melting temperature varies thl b t th t d b smoothly between the two endmembers.

As liquid olivine cools, it eventually begins to solidify.

We could logically expect that to happen somewhere between the melting points of forsterite and fayalite. The resulting solid would not be pure forsterite, but since forsterite has the higher melting point we since forsterite has the higher melting point, we would expect the solid to be richer in forsterite than the melt. The melt and solid compositions when crystallization first begins are shown in red and blue, respectively.

At T

1 (1890 ºC)

All liq uid
Co mpo sitio n:

Mg 50%

At T

2 (1700 ºC)

Mo stly liq uid & so me

so lid

Co mpo sitio n:

M 50% M 80% Mg 50% F e 50% Mg 50% Mg 80% F e 50% F e 20% (L iq uid) (So lid)

At T

3 (1575 ºC)

L

iq uid & so lid C i i

At T

4 (1450 ºC)

Mo stly so lid & so me

liq uid

Co mpo sitio n:

Mg 30% Mg 65% F e 70% F e 35% (L iq uid) (So lid) liq uid

Co mpo sitio n:

Mg 18% Mg 50% F e 82% F e 50% (L iq uid) (So lid)

As a system of given composition cools, it eventually

encounters the liquidus (T2). Solid begins to form. As forsterite rich crystals solidify, the melt becomes enriched in fayalite and slides down the liquidus (T3). Th lid iti lid d th lid (T3) The solid composition slides down the solidus (T3). Eventually, the solid composition equals that of the initial melt (T4).

At that point the system has completely solidified.

The last remnant of the melt is on the liquidus at T4. The overall system of course does not change The overall system, of course, does not change composition but drops straight down from T1 to T4. Between T1 and T4, the position of the overall system relative to the melt and solid points gives the proportions of melt and solid.