Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Metapelite is an old and currently not widely used field geological term for a clay rich fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone
Discoverer
Unknown
Unknown
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From Pelos or clay in Greek
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Porphyritic
Foliated
Color
Black, Brown, Green, Grey, Red, Rust, White
Dark Greenish - Grey, Green, Light Green, Light Greenish Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Construction Aggregate
Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Commemorative Tablets, Creating Artwork
Types
Rhomb Porphyry
Metamorphic rock
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Easily splits into thin plates, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Formation
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Metapelite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Albite, Chlorite, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Irregular
Fibrous
Porosity
Less Porous
Highly Porous
Specific Gravity
2.5-4
3.4-3.7
Transparency
Translucent to Opaque
Opaque
Density
2.5-2.52 g/cm3
0-300 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
-
Africa
Egypt, Ethiopia, Ghana, South Africa
Western Africa
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
United Kingdom
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
-
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
Central Australia, Western Australia
Porphyry vs Metapelite 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. Porphyry vs Metapelite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Porphyry and Properties of Metapelite. Learn more about Porphyry vs Metapelite in the next section. The interior uses of Porphyry include Decorative aggregates and Interior decoration whereas the interior uses of Metapelite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Porphyry and Metapelite, they have various applications in construction industry. The uses of Porphyry in construction industry include Construction aggregate and that of Metapelite include Cement manufacture, Construction aggregate, For road aggregate.
More about Porphyry and Metapelite
Here you can know more about Porphyry and Metapelite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Porphyry and Metapelite consists of mineral content and compound content. The mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica and mineral content of Metapelite includes Albite, Chlorite, Quartz. You can also check out the list of all Igneous Rocks. When we have to compare Porphyry vs Metapelite, the texture, color and appearance plays an important role in determining the type of rock. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas, Metapelite is available in dark greenish - grey, green, light green, light greenish grey colors. Appearance of Porphyry is Dull and that of Metapelite is Banded. Properties of rock is another aspect for Porphyry vs Metapelite. The hardness of Porphyry is 6-7 and that of Metapelite is 5-6. The types of Porphyry are Rhomb Porphyry whereas types of Metapelite are Metamorphic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Porphyry is white while that of Metapelite is . The specific heat capacity of Porphyry is 0.71 kJ/Kg K and that of Metapelite is 0.72 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Porphyry is heat resistant, impact resistant whereas Metapelite is heat resistant, impact resistant, pressure resistant.