Definition
Trachyandesite is an extrusive igneous rock.
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Discoverer
Unknown
Unknown
Etymology
From French trachyandésite, trachy + andésite andesite, a lava intermediate in composition between trachyte and andesite
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Porphyritic
Color
Black, Brown, Light to Dark Grey
Black, Brown, Colourless, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Dull
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Cobblestones, for Road Aggregate, Rail Track Ballast, Roadstone
Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Pottery
Creating Artwork, Gemstone, Jewelry
Types
Basaltic Trachyandesite
Rhomb Porphyry
Features
Has High structural resistance against erosion and climate, Very fine grained rock
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
Used
Not Used
Petroglyphs
Used
Not Used
Formation
Trachyandesite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
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
Alkali feldspar, Biotite, Olivine, Plagioclase, Pyroxene, Sodic plagioclase
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Cataclastic Metamorphism, Contact 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, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Irregular
Streak
Light to dark brown
White
Porosity
Less Porous
Less Porous
Compressive Strength
Not Available
Cleavage
Perfect
Imperfect
Specific Gravity
2.8-3
2.5-4
Transparency
Opaque
Translucent to Opaque
Density
2.9-3.1 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
India, Russia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
South Africa
Egypt, Ethiopia, Ghana, South Africa
Europe
Iceland
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
Canada, USA
Canada, Cuba, Jamaica, USA
South America
Brazil
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
Not Yet Found
New South Wales, New Zealand, Western Australia
All about Trachyandesite and Porphyry Properties
Know all about Trachyandesite and Porphyry properties here. All properties of rocks are important as they define the type of rock and its application. Trachyandesite and Porphyry belong to Igneous Rocks.Texture of Trachyandesite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Porphyry is Porphyritic. Trachyandesite appears Dull and Soft and Porphyry appears Dull. The luster of Trachyandesite is earthy while that of Porphyry is dull. Trachyandesite is available in black, brown, light to dark grey colors whereas Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors. The commercial uses of Trachyandesite are creating artwork, pottery and that of Porphyry are creating artwork, gemstone, jewelry.