Definition
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
History
Origin
-
New Zealand
Discoverer
Alexandre Brongniart and René Just Haüy
Unknown
Etymology
From Greek trakhus rough’ or trakhutēs roughness
From Greek mulōn mill + -ite
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Foliated
Color
Black, Brown, Dark Greenish - Grey, Green, Grey, Light to Dark Grey, White
Black to Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Banded
Dull, Banded and Foilated
Architecture
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
for Road Aggregate, Landscaping, Roadstone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments
Other Uses
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Gemstone, Jewelry
Types
Felsic volcanic rock
Blastomylonites, Ultramylonites and Phyllonites
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
Surfaces are often shiny
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Trachyte is an igneous volcanic rock with an aphanitic to porphyritic texture. It is the volcanic equivalent of syenite rock and forms as a result of magmatic differentiation.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Composition
Mineral Content
Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz
Porphyroblasts
Compound Content
Potassium Oxide, Sodium Oxide, Silicon Dioxide
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Regional 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, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Physical Properties
Hardness
63-4
1
7
👆🏻
Grain Size
Fine Grained
Fine Grained
Fracture
-
Conchoidal
Streak
White
White
Porosity
Less Porous
Highly Porous
Luster
Metallic
Shiny
Compressive Strength
150.00 N/mm21.28 N/mm2
0.15
450
👆🏻
Cleavage
-
Conchoidal
Toughness
-
-
Specific Gravity
2.72.97-3.05
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.43-2.45 g/cm32.6-4.8 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K1.50 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
China, India, Indonesia, Saudi Arabia, South Korea
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Europe
Bulgaria, England, Germany, Norway, Romania, Switzerland
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Others
-
-
Deposits in Western Continents
North America
USA
USA
South America
Brazil, Chile
-
Deposits in Oceania Continent
Australia
New Zealand, Queensland, South Australia, Western Australia
Central Australia, Western Australia