Definition
Quartzite is a non-foliated metamorphic rock that forms by the metamorphism of pure quartz Sandstone
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
History
Origin
-
Ethiopia
Discoverer
Unknown
Obsius
Etymology
From quartz + -ite
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Volcanic
Other Categories
Medium Grained Rock, Opaque Rock
Opaque Rock
Texture
Foliated, Granular
Glassy
Color
Black, Blue, Brown, Green, Light Grey, Purple, White, Yellow
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Lustrous
Shiny
Architecture
Interior Uses
Countertops, Decorative Aggregates, Flooring, Homes
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Garden Decoration
Other Architectural Uses
Curbing
-
Industry
Construction Industry
Arrowheads, As Dimension Stone, Cement Manufacture, Construction Aggregate, Cutting Tool, for Road Aggregate, Making natural cement, Production of Glass and Ceramics, Rail Track Ballast, Roadstone
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
-
Surgery
Antiquity Uses
Artifacts, Jewellery, Monuments, Sculpture
Artifacts, Jewellery
Other Uses
Commercial Uses
An Oil and Gas Reservoir, As armour rock for sea walls, Cemetery Markers, Commemorative Tablets, In aquifers, Laboratory bench tops, Petroleum reservoirs, Soil Conditioner, Source of Magnesia (MgO), Tombstones, Used in aquariums
Creating Artwork, Mirror, Used in aquariums
Types
Orthoquartzite and Metaquartzite
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Generally rough to touch, Is one of the oldest rock
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Quartzite forms from sandstone and the mineral quartz being put under extreme heat and pressure.
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.
Composition
Mineral Content
Chlorite, Epidote, Hematite, Kyanite, Magnetite, Muscovite or Illite, Quartz
-
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, MgO, Sodium Oxide, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Hydrothermal Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Physical Properties
Hardness
6-75-5.5
1
7
👆🏻
Grain Size
Medium Grained
-
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Streak
White
White
Porosity
Less Porous
Very Less Porous
Luster
Vitreous
Vitreous
Compressive Strength
115.00 N/mm20.15 N/mm2
0.15
450
👆🏻
Cleavage
Indiscernible
-
Toughness
1.9
-
Specific Gravity
2.6-2.82.6-2.7
0
8.4
👆🏻
Transparency
Transparent to Translucent
Translucent
Density
2.32-2.42 g/cm32.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.75 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Israel, Russia, South Korea, Thailand, Turkey
Afghanistan, Indonesia, Japan, Russia
Africa
Ethiopia, Morocco, South Africa, Zimbabwe
Kenya
Europe
England, Italy, Norway, Scotland, Sweden, United Kingdom
Greece, Hungary, Iceland, Italy, Turkey
Others
Greenland
-
Deposits in Western Continents
North America
Bahamas, Canada, USA
Canada, Mexico, USA
South America
Brazil, Colombia, Venezuela
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New Zealand, Queensland, Western Australia
New Zealand