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
Ignimbrite is a volcanic rock consisting mainly of pumice fragments, formed by the consolidation of material deposited by pyroclastic flows
Origin
Ethiopia
New Zealand
Discoverer
Obsius
Patrick Marshall
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Latin ignis fire + imber, imbr- shower of rain, storm cloud + -ite
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Beige, Black, Brown, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Dull, Vesicular and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
-
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Building houses or walls, Construction Aggregate
Medical Industry
Surgery
-
Antiquity Uses
Artifacts, Jewellery
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Pyroclastic rock
Features
Blocks negativity, Helps to protect against depression
Always found as volcanic pipes over deep continental crust
Archaeological Significance
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.
Ignimbrites are formed from very poorly sorted mixture of volcanic ash or tuff and pumice lapilli, commonly with scattered lithic fragments.
Mineral Content
-
Apatite, Biotite, Calcite, Chlorite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, NaCl
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion
Grain Size
-
Fine Grained
Fracture
Conchoidal
Uneven
Porosity
Very Less Porous
Highly Porous
Luster
Vitreous
Vitreous to Dull
Specific Gravity
2.6-2.7
2.73
Transparency
Translucent
Opaque
Density
2.6 g/cm3
1-1.8 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
Africa
Kenya
Cameroon, Cape Verde, Chad, Djibouti, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Tanzania, Uganda
Europe
Greece, Hungary, Iceland, Italy, Turkey
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
Others
-
Antarctica, Hawaii Islands
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, Costa Rica, Panama, USA
South America
Argentina, Chile, Ecuador, Peru
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador
Deposits in Oceania Continent
Australia
New Zealand
Central Australia, Western Australia
Obsidian vs Ignimbrite Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Obsidian vs Ignimbrite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Ignimbrite. Learn more about Obsidian vs Ignimbrite in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Ignimbrite include Decorative aggregates, Floor tiles, Homes and Interior decoration. Due to some exceptional properties of Obsidian and Ignimbrite, they have various applications in construction industry. The uses of Obsidian in construction industry include Arrowheads, Cutting tool, Knives, Scrapers, Spear points and that of Ignimbrite include Building houses or walls, Construction aggregate.
More about Obsidian and Ignimbrite
Here you can know more about Obsidian and Ignimbrite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Ignimbrite consists of mineral content and compound content. The mineral content of Obsidian includes and mineral content of Ignimbrite includes Apatite, Biotite, Calcite, Chlorite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Ignimbrite, the texture, color and appearance plays an important role in determining the type of rock. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas, Ignimbrite is available in beige, black, brown, grey, pink, white colors. Appearance of Obsidian is Shiny and that of Ignimbrite is Dull, Vesicular and Foilated. Properties of rock is another aspect for Obsidian vs Ignimbrite. The hardness of Obsidian is 5-5.5 and that of Ignimbrite is 4-6. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Ignimbrite are Pyroclastic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Obsidian and Ignimbrite is white. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Ignimbrite is 0.20 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Obsidian is heat resistant, impact resistant whereas Ignimbrite is heat resistant, impact resistant, pressure resistant, wear resistant.