Definition
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.
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Origin
Tonale, Italy
Egypt
Discoverer
Unknown
Unknown
Etymology
Not Available
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Phaneritic
Porphyritic
Color
Black, Brown, Light to Dark Grey, White
Black, Brown, Colourless, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Banded and Foilated
Dull
Interior Uses
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate
Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Gemstone, Jewelry
Types
Not Available
Rhomb Porphyry
Features
Is one of the oldest rock, Typically speckled black and white.
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Formation
When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.
Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.
Mineral Content
Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
NaCl, CaO, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Not Registered
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Irregular
Streak
Bluish Black
White
Porosity
Very Less Porous
Less Porous
Luster
Subvitreous to Dull
Dull
Cleavage
Not Available
Imperfect
Specific Gravity
2.86-3
2.5-4
Transparency
Opaque
Translucent to Opaque
Density
2.73 g/cm3
2.5-2.52 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Not Yet Found
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
Egypt
Egypt, Ethiopia, Ghana, South Africa
Europe
Finland, Germany, Italy, Romania, Sweden, Turkey
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
USA
Canada, Cuba, Jamaica, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New South Wales, New Zealand, Western Australia