Obsidian

Nepheline Syenite

Obsidian and Nepheline Syenite

Obsidian

Nepheline Syenite

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1 Definition

1.1 Definition

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth

Nepheline Syenite is a holocrystalline plutonic rock resembling syenite but containing nepheline and lacking quartz

1.2 History

1.2.1 Origin

Ethiopia

Unknown

1.2.2 Discoverer

Obsius

Unknown

1.3 Etymology

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

From origin of a Palaeozoic nepheline syenite from northern Shanxi Province, China

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Volcanic

Plutonic

1.6 Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Granular

2.2 Color

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

Brown, Buff, Cream, Green, Grey, Pink, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Shiny

Banded and Foilated

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, Flooring, Homes, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

3.1.3 Other Architectural Uses

Not Yet Used

Curbing

3.2 Industry

3.2.1 Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories, Production of Glass and Ceramics

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Artifacts, Monuments, Sculpture

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Cemetery Markers, Creating Artwork

4 Types

4.1 Types

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

Borolanite and Litchfieldite

4.2 Features

Blocks negativity, Helps to protect against depression

Application of acids on the surface causes cloudy frosting, Available in Lots of Colors and Patterns, Dissolves in hydrochloric acid, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

Used

4.3.2 Famous Monuments

Not Applicable

Data Not Available

4.3.3 Sculpture

Not Yet Used

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Used

4.3.6 Petroglyphs

Used

4.3.7 Figurines

Not Yet Used

Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

Nepheline Syenites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.

5.2 Composition

5.2.1 Mineral Content

Not Available

Albite, Amphibole, Biotite, Cancrinite, Feldspar, Hornblende, Plagioclase, Pyroxene, Sodalite

5.2.2 Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Impact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.55.5-6

1 7

6.1.2 Grain Size

Not Applicable

Fine Grained

6.1.3 Fracture

Conchoidal

Conchoidal to Uneven

6.1.4 Streak

White

6.1.5 Porosity

Very Less Porous

Less Porous

6.1.6 Luster

Vitreous

Greasy to Dull

6.1.7 Compressive Strength

0.15 N/mm²150.00 N/mm²

0.15 450

6.1.8 Cleavage

Non-Existent

Poor

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.6-2.72.6

0 8.4

6.1.11 Transparency

Translucent

Translucent to Opaque

6.1.12 Density

2.6 g/cm³2.6 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg KNA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

Indonesia, Iran, Russia, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Turkmenistan, Vietnam

7.1.2 Africa

Kenya

Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Andorra, Finland, France, Great Britain, Italy, Norway, Portugal, Spain, Sweden

7.1.4 Others

Not Yet Found

Greenland

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Canada, USA

7.2.2 South America

Argentina, Chile, Ecuador, Peru

Brazil, Chile, Colombia, Uruguay, Venezuela

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand

New Zealand, Queensland, South Australia, Tasmania, Western Australia

All about Obsidian and Nepheline Syenite Properties

Know all about Obsidian and Nepheline Syenite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Nepheline Syenite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Nepheline Syenite is Granular. Obsidian appears Shiny and Nepheline Syenite appears Banded and Foilated. The luster of Obsidian is vitreous while that of Nepheline Syenite is greasy to dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Nepheline Syenite is available in brown, buff, cream, green, grey, pink, white colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Nepheline Syenite are cemetery markers, creating artwork.