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
Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.
Origin
Ethiopia
Tonale, Italy
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Not Available
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy
Phaneritic
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Light to Dark Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Banded and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts, Jewellery
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Creating Artwork
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Not Available
Features
Blocks negativity, Helps to protect against depression
Is one of the oldest rock, Typically speckled black and white.
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Used
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.
When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.
Mineral Content
Not Available
Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
NaCl, CaO, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Not Applicable
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White
Bluish Black
Porosity
Very Less Porous
Very Less Porous
Luster
Vitreous
Subvitreous to Dull
Compressive Strength
Not Available
Cleavage
Non-Existent
Not Available
Toughness
Not Available
2.1
Specific Gravity
2.6-2.7
2.86-3
Transparency
Translucent
Opaque
Density
2.6 g/cm3
2.73 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Not Yet Found
Europe
Greece, Hungary, Iceland, Italy, Turkey
Finland, Germany, Italy, Romania, Sweden, Turkey
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Argentina, Chile, Ecuador, Peru
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
New Zealand
New Zealand, South Australia, Western Australia
Obsidian vs Trondhjemite 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 Trondhjemite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Trondhjemite. Learn more about Obsidian vs Trondhjemite in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Trondhjemite include Decorative aggregates, Entryways, Flooring, Homes and Interior decoration. Due to some exceptional properties of Obsidian and Trondhjemite, 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 Trondhjemite include As dimension stone, Cement manufacture, Cobblestones, Construction aggregate, For road aggregate.
More about Obsidian and Trondhjemite
Here you can know more about Obsidian and Trondhjemite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Trondhjemite consists of mineral content and compound content. The mineral content of Obsidian is not available and mineral content of Trondhjemite includes Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Trondhjemite, 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, Trondhjemite is available in black, brown, light to dark grey, white colors. Appearance of Obsidian is Shiny and that of Trondhjemite is Banded and Foilated. Properties of rock is another aspect for Obsidian vs Trondhjemite. The hardness of Obsidian is 5-5.5 and that of Trondhjemite is 6-7. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Trondhjemite are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Obsidian is white while that of Trondhjemite is bluish black. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Trondhjemite is 0.92 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 Trondhjemite is heat resistant, pressure resistant, wear resistant.