Rocks & Mineral Description

SAMPLE-1

Colour: variable -generally black,gray,brown.

Layer: yes .

Streak : black.

Shiny :light sheen.

Texture:

- very fine particles,smooth.

-silt size & clay size mineral size particles.

-Shape: Variable

Visible Minerals: quartz, feldspar,chert .

Reaction with HCL: yes

Hardness : 3 on the Moh's scale

Specific Gravity: 2.4-2.8 .

Conclusion: From the above characteristics, we can identify that the sample is a clastic

sedimentary rock Shale

SAMPLE-2

Color:Colorless or white; also blue, purple, red, pink, yellow, orange, or gray

Fracture: Brittle

Luster: Vitreous

Streak: White

Texture: Crystalline texture

Crystal size: less than 1 cm

Grain Size: mostly fine grained

Crystal Shape: cubic

Visible minerals: Halite; mostly sodium chloride (NaCl)

Hardness: 2.0 - 2.5 on Mohs scale

Reaction with HCl: no reaction

Specific gravity: 2.17

Decision: From the above characteristics, we can identify that the sample is a chemical

sedimentary rock, "Rock salt" also known as "Halite".

SAMPLE-3

Color: Variable,white,grey,reddish

Texture: Granoblastic texture

--Grain Size: Medium grained

--Shape: Angular

Visible minerals: Can see interlocking quartz crystal with naked eye.

Hardness: 6.5-7

Reaction with HCl: No reaction

Density: 2.3-2.4 Kg/cm3

Specific Gravity: 2.6-2.8

Decision: From the above characteristics, we can identify that the sample is a

metamorphic rock Quartzite.

SAMPLE-4

Colour:Iron black, black

Transparency: Opaque

Texture:

Crystal size: Massive, lamellar,distinctively foliated,finely grained

Crystal shape: Tabular, trigonal,rhombohedral

Luster: Metallic, sub-metallic

Streak:Black

Cleavage:Absent

Fracture:Conchoidal to subconchoidal

Hardness:5-5.5 on Mohs scale Reactionwith HCl: No reaction

Density:4.72 gm/cm3

Specificgravity: 4.70-4.79

Conclusion: From the above characteristics we can identify the given sample as Ilmenite

(FeTiO3 ).

SAMPLE-5

Color: White, yellow, green, gray, brown, black, purple; sometimes multicolored,

especially green and yellow

Texture:

grain size/crystal size: 0.05 to 6 mm

Sorting:Poorly sorted

Visible minerals: Serpentine

Hardness: 2-5

Reaction with HCl: No

Density: 2.7 to 3.3

Specific gravity: 2.5-3.2


metamorphic rock Serpentinite

SAMPLE-6

Colour : Purple,rosy,silver,white,yellowish,green,gray,sometimes colorless and

transparent

Texture : Layered or platy

Lustre : vitreous to pearly

Streak : Colourles

Hardness : 2.5 to 3

Reaction with HCL : No

Density : 3.03 gm/cm3

Specific gravity : 2.8 to 3.1

Crystal system : Monoclinic

Cleavage : Perfect

Fracture : Uneven

Conclusion : Observing above properties we may take a leap of suggesting this rock as

Mica.

SAMPLE-7

Crystal System: Massive, monoclinic

Formula: CaSO4.2H2O

Color: Colorless to white

Streak: White

Luster: Vitreous to pearly

Fracture: Conchoidal

Cleavage: Perfect

Tenacity: Flexible

Hardness: 2

Specific Gravity: 2.3

Diaphaneity: Transparent to translucent

Conclusion: From the above characteristics we can identify the given sample as Gypsum

SAMPLE-8

Colour : Green,Grey,Brown

Layer : yes

Streak : white powdery

Texture: Foliated

Size :Medium grained

Visible minerals : Quartz,mica,feldspar,talc

Reaction with HCl : No

Hardness : Generally hard

Specific gravity : 2.5-2.9

Conclusion:From the above characteristics we can say that the sample is Schist.

SAMPLE-9

Colour:black to brownish black or grey

Texture:

-fine-medium grain size

-course sorting

-variable shape

Visible minerals: no visible minerals

Hardness: 2.2

Reaction with HCl: yes

Density: 833 to 1506 kg/m3

Specific gravity: 1.1 to 1.4

Conclusion: From above characteristics we can say that the sample is coal.

SAMPLE-10

Color: Grey, Green, Red, Black, Purple and Brown

Texture: Foliated

Grain size/crystal size: Fine-grained

Shape: Flat

Visible minerals: No mineral is visible with the naked eye

Hardness: 3.0 to 4.0 on Moh's scale


Density: 2.6 to 2.8 Kg/cm3



metamorphic rock Shale

SAMPLE-11

Crystal system: cubic, massive

Formula: FeO + Fe2O3 = Fe3O4

Color: Black

Streak: Black

Luster: Metallic

Fracture: Subconchoidal

Teracity: Brittle

Moh's scale of hardness: 6

Specific gravity: 5

Magnetism: Strongly magnetic

Decision: From the above characteristics, we can identify that the sample is Magnetite

SAMPLE-12

Colour: variable - generally alternating lighter and darker sub-parallel discontinuous

bands.

Texture: Foliated Texture

-Grain Size/Crystal Size: medium to coarse grained; can see crystals with the naked eye.

-Shape: Variable

Visible Minerals: In light bands: quartz, feldspar etc And in Dark bands: biotite, graphite

etc.

Hardness: 7

Reaction with HCl: No Reaction

Density: 2.6 - 2.9 gm/cm3


Conclusion: From the above characteristics, we can say that the sample is a metamorphic

rock Gneiss

SAMPLE-13

Rock type: volcanic (igneous)

Color: Intermediate to felsic (dark gray to light tan).

Texture: aphanitic to porphyritic texture.

Grain Size/Crystal Size: Fine-grained to medium-grained.

Visible Minerals: plagioclase pyroxene, quartz, biotite and hornblende.

Hardness: 7 (MHS)


Specific gravity (density): 2.5-2.8

Conclusion: From the above characteristics, we can say that the sample is Andesite

SAMPLE-14

Colour : variable- Light tan to pink

Texture : clastic or non-clastic

--Grain size : usually very fine-grained

--Shape : smooth to rough

Visible mineral : Calcite

Hardness : generally hard, 3 to 4 on Mohs scale Density : 2.5 to 2.7 kg/cm3

Reaction wiht HCl : Yes; release bubbles of carbon dioxide gas

Specific Gravity : 2.20 to 2.60

Water absorption : Less than 1%

Porosity : Quite low

Conclusion: From the above characteristics, we can say that the sample is Limestone

SAMPLE-15

Colour: White, pink, or gray in colour. It depends on their mineralogy.

Texture: Granular and Phaneritic.

Grain size/Crystal size: Large and coarse grain size and highly visible crystal.

Shape: Variable.

Sorting: Poorly sorted.

Visible Mineral: Quartz, Biotite Mica, Potassium Feldspar.

Hardness: 6 to 7 on Moh's Scale.

Density:2.6 to 2.8 Kgcm^-3


Reaction With HCl: Yes.

Conclusion: From the above characteristics, we can identify that the sample is a felsic

intrusive igneous rock Granite

SAMPLE-16

Formula: Aluminium Oxide, Al2O3

colour: Colorless, Gray, Brown; Pink to red

Crystal system: Trigonal.

cleavage: None.

Fracture: Conchoidal to uneven.

Tenacity: Brittle.


Streak: White

Diaphaneity: Transparent.

Conclusion: From the above characteristics, we can say that the sample is Corrundum

SAMPLE-17

Colour: grey to dark grey.

Texture: medium to coarse grained

Shape:variable shape.

Texture:phaneritic

Visible minerals: plagioclase, amphibole, pyroxene etc.

Hardness: 7

Reaction with HCl: yes.


Decision: from above characteristics, we can say that the sample rock is a diorite rock.

SAMPLE-18

Color: colorless or white,also gray, yellow, green

Texture:

Grain size: mixture

Shape: Calcite crystals form in a wide variety of shapes, but tend to break into

rhombohedrons (six-sided solids that resemble cubes except that the faces meet at 60

degree instead of 90 degree)

Sorting: well-sorted

Visible minerals: quartz

Hardness: 3

Reaction with HCl: 2HCl + CaCO3--> CaCl2 + H2O + CO2

Density:2.71 gm/cc

Specific gravity: 2.71

Decision: from above characteristics, we can say that the sample rock is Calcite

SAMPLE-19

Color: variable

Texture: clastic(coarse-grained)

-grain size: >2mm

-Shape: angular

-sorting: poorly sorted

visible minerals: no visible minerals

Hardness: variable, soft to hard

reaction with HCl: no reaction

Density: 2-2.5 g/cm

Decision: From the above characteristics, we can identify that the sample is breccia.

SAMPLE-20

Colour : green, grey, dark brown (biotite schist)silver (muscovite schist)

Texture: foliated

Grain size: medium

Visible minerals : visible grains of mica

Hardness: 1 on Moh's scale

Reaction with HCl: no

Specific gravity : 2.5-2.9

Decision: From the above characteristics, we can identify that the sample is Mica Schist

SAMPLE-21

Colour: dark green, dark grey, dark red, green

Texture : phaneritic

Crystal size: usually over 5 cm in size

Hardness : 7 on moh's scale

Reaction with HCl: no

Decision: From the above characteristics, we can identify that the sample is Pegmatite

SAMPLE-22

Colour: white, grey, pink

luster: pearly to vitreous to dull

Streak: white

Cleavage: perfect in three directions.

Fracture: choncoidal

Hardness: 3.5-4

Sp. gravity : 2.86

Reaction with HCl : yes

Decision: From the above characteristics, we can identify that the sample is Dolomite

SAMPLE-23

Colour: bright white, grey, black

Texture : non foliated

Visible minerals : visible crystals of Calcite Hardness : 3-4 on Moh's scale

Sp. gravity : 2.4-2.7

Reaction with HCl : yes

Decision: From the above characteristics, we can identify that the sample is Marble

SAMPLE-24

Color:Dark,grey or black

Texture:aphanitic (can be porphyritic).

-grain size/crystal size:fine grain

-Shape:variable(mainly rectangular)

-sorting:poorly sorted

visible minerals:none

Hardness:2.3

reaction with HCl:no reaction

Density:1954 kg/cu.m.

Specific gravity:2.8-3

Decision: From the above characteristics, we can identify that the sample is basalt.

SAMPLE-25

Color: greenish or dark-colored

Texture: usually equigranular

-grain size/crystal size: coarse grained, with crystals in the size range of 1 mm or greater

-Shape: Variable

-sorting: Poorly sorted

visible minerals: no visible minerals

Hardness: 1.6

reaction with HCl: no reaction

Density: 2700-3300 kg/m3


Decision: From the above characteristics, we can identify that the sample is Gabbro.

SAMPLE-26

Color-varies from red,green,yellow,gray and white.

texture-clastic

grain size-.06-2 mm

Shape-rounded

Sorting-arenaceous or argillaceous

Visible minerals-feldspar and quartz

Hardness-6.5 to 7 moh's scale

React. with hcl-no reac.

Density-2.32 to 2.42 kg/cm3

Sp. Gr.-2.2-2.8

Decision: From the above characteristics, we can identify that the sample is Sandstone

SAMPLE-1

Crystal system: Orthorombic

Color: Yellow

Streak: white

Fracture: uneven

Luster: Resinous

Hardness: 2


Diaphaneity: Transparent to translucent

Decision: From the above characteristics, we canidentify that the sample is a mineral which name is Sulfur

SAMPLE-2

Crystal System: Trigonal

Color: Reddish Brown to Black

Luster: Metalic to dull

Streak: Light to dark red

Formula: Fe2O3

Fracture: Uneven

Hardness: 6


Diaphaneity: Opaque

Decision: From the above characteristics, we canidentify that the sample is a mineral which name is

Hematite.

SAMPLE-3

Crystalsystem : Triclinic

Color :Blue darker in the centre

Streak :White

Luster:Pearly

Formula: Al2SiO5

Clevage :Perfect (100)

Fracture :Uneven

Moh's scale of hardness : 5

Specific gravity : 3.6


Kyanite

SAMPLE-4

Crystalsystem : Hexagonal

Color : Yellowor White

Streak :White

Luster :Vitreous

Formula: Be3Al2 ( Si6O18 )

Clevage : NoClevage

Fracture :Conchoidal

Diaphaneity: Transparent to Translucent

Moh's scale of hardness : 7.5

Specific gravity : 2.7

Decision: From the above characteristics, we canidentify that the sample is a mineral which name is Beryl

SAMPLE-5

Crystal System: Cubic massive

color: Black to brown

Streak: Dark brown

Luster: Metallic

Formula FeO + Cr2O3 +FeCr2O4

Fracture: Uneven: 5.5


ternacity: Brittle

Diaphaneity: translucent to opaque


Chromite

SAMPLE-6

Color: black and opaque

Chemical formula: Ferrous-Ferric Oxide Fe3O4

Streak: blackLuster: metallic,greasy, dull

Transparency: opaque

Crystal system: cubic


Hardness (Mohs): 5.5

Cleavage: imperfect

Fracture: conchoidal


Magnetite

SAMPLE-7

Formula: Al2Si4O10(OH)2

Color : White , gray , pale blue or green , brownish yellow

.Crystal system : Monoclinic .

Cleavage : Perfect

Fracture : Uneven .

Tenacity : Flexible , inelastic .

Mohs scale hardness : 1 - 2 .

Luster : Pearly to dull .

Streak : White .

Specific gravity : 2.65 - 2.9 .

Diaphaneity : Translucent to opaque .

Decision : From the above characteristics, we can identify that the sample is a mineral named Prophyllite

SAMPLE-8

Formula: MgCO3

Color : Colorless , white , pale yellow , pale brown

.Crystal system : Trigonal .

Cleavage : Perfect .

Fracture : Conchoidal to uneven .

Tenacity : Brittle

. Mohs scale hardness : 3.5 - 4.5

.Luster : Vitreous

. Streak : White .

Diaphaneity : Transparent to translucent .

Specific gravity : 3.0 - 3.2 . Decision : From the above characteristics, we can identify that the sample is a mineral named Magesite

SAMPLE-9

Formula: MnO2

Crystal habit : Granular to massive

Crystal system : Tetragonal

color: Black to lighter gray

Cleavage : perfect

Fracture: Brittle

Mohs scale Hardness: 6-6.65

Specific Gravity : 4.4-5.06

Streak : Black


Pyrolusite

SAMPLE-10

Crystal system: triclinic or monoclinic

Color: White, gray, brown

Streak: white

luster : vitreous

Mhos scale Hardness: 6-6.5


Diaphaneity: opaque


Feldspar

SAMPLE-11

Formula: K(Mg,Fe)3(AlSi3O10)(F,OH)2

Crystal system: Monoclinic

Color: Brown, Black

Streak: Colourless

Luster: Vitreous

Cleavage: Perfect basal

Fracture: Uneven

DiaphaneityTransparent to translucent

Magnetism: None

Hardness: 2 - 3

Density: 2.7 - 3.4

Specific gravity:2.73.1

Reaction with HCl: Very weak

Decision : From the above characteristics, we can identify that the sample is a mineral named

Biotite.

SAMPLE-12

Formula:Mg3Si4O10(OH)2

Crystal System: Monoclinic

Colour: White, or brownish, dark green, gray

Streak: White

Luster: Grease

Cleavage: Perfect

Fracture: Uneven

Diaphaneity: Translucent

Magnetism: None

Hardness: 1

Density: 2.6 - 2.8


Reaction with HCl: Unknown

Decision : From the above characteristics, we can identify that the sample is a mineral named

Talc.

SAMPLE-13

Crystal System: Massive, Monoclinic.

Formula: CaSO4.2H2O

Color: Colorless

Streak: White

Luster: Vitreous to Pearly

Clevage: Perfect

Tenacity: Flexible

Mohs scale Hardness : 2



Gypsum

SAMPLE-14

Crystal System: Hexagonal

Crystal habit: Tabular

Color: Iron black to steel grey

Streak: Black

Luster: Metallic

Hardness: 1-2

Diaphaneity: Opaque

Tenacity: Sectile


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Rocks & Mineral Description