Definition
Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate
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.
History
Origin
-
Tonale, Italy
Discoverer
Unknown
Unknown
Etymology
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
From Trondheim, Norway
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Polished
Phaneritic
Color
Dark Grey to Black, Pink, Red, White
Black, Brown, Light to Dark Grey, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Rough and Dull
Banded and Foilated
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing, Whetstones
Curbing
Industry
Construction Industry
Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Fire resistant, Used to manufracture paperweights and bookends
Cemetery Markers, Creating Artwork
Types
Metamorphic rock
Intermediate intrusive rock
Features
Is one of the oldest rock
Is one of the oldest rock, Typically speckled black and white.
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Present
Absent
Formation
An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.
When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.
Composition
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon
Compound Content
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
NaCl, CaO, MgO, Silicon Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
2-36-7
1
7
👆🏻
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal to Uneven
Conchoidal
Streak
White to Grey
Bluish Black
Porosity
Highly Porous
Very Less Porous
Luster
Waxy and Dull
Subvitreous to Dull
Compressive Strength
-130.00 N/mm2
0.15
450
👆🏻
Cleavage
Slaty
-
Toughness
2.6
2.1
Specific Gravity
2.56-2.682.86-3
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.54-2.66 g/cm32.73 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.87 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
-
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Egypt
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Finland, Germany, Italy, Romania, Sweden, Turkey
Others
-
-
Deposits in Western Continents
North America
USA
USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New Zealand, South Australia, Western Australia