Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals
Discoverer
Unknown
Unknown
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From Old French pomis, from a Latin dialect variant of pumex
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Vesicular
Color
Black, Brown, Green, Grey, Red, Rust, White
Beige, Grey, Light Green, Light Grey, Pink, White, Yellow- grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull
Vesicular
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing, Powder
Construction Industry
Construction Aggregate
As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks
Medical Industry
-
As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
Creating Artwork, Gemstone, Jewelry
As a traction material on snow-covered roads, As an abrasive in pencil erasers, Fine abrasive used for polishing, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Used in aquariums
Types
Rhomb Porphyry
Scoria
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Host Rock for Lead
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.
Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Impact 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, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Irregular
Planar
Streak
White
White, Greenish White or Grey
Porosity
Less Porous
Highly Porous
Specific Gravity
2.5-4
2.86
Transparency
Translucent to Opaque
Opaque
Density
2.5-2.52 g/cm3
0.25-0.3 g/cm3
Resistance
Heat Resistant, Impact Resistant
Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Afghanistan, Indonesia, Japan, Russia
Africa
Egypt, Ethiopia, Ghana, South Africa
Ethiopia, Kenya, Tanzania
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Greece, Hungary, Iceland, Italy, Turkey
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
New Zealand, Western Australia
Porphyry vs Pumice 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 Pumice characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Porphyry and Properties of Pumice. Learn more about Porphyry vs Pumice in the next section. The interior uses of Porphyry include Decorative aggregates and Interior decoration whereas the interior uses of Pumice include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Porphyry and Pumice, they have various applications in construction industry. The uses of Porphyry in construction industry include Construction aggregate and that of Pumice include As dimension stone, Cement manufacture, For road aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks.
More about Porphyry and Pumice
Here you can know more about Porphyry and Pumice. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Porphyry and Pumice consists of mineral content and compound content. The mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica and mineral content of Pumice includes Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica. You can also check out the list of all Igneous Rocks. When we have to compare Porphyry vs Pumice, 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, Pumice is available in beige, grey, light green, light grey, pink, white, yellow- grey colors. Appearance of Porphyry is Dull and that of Pumice is Vesicular. Properties of rock is another aspect for Porphyry vs Pumice. The hardness of Porphyry is 6-7 and that of Pumice is 6. The types of Porphyry are Rhomb Porphyry whereas types of Pumice are Scoria. 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 Pumice is white, greenish white or grey. The specific heat capacity of Porphyry is 0.71 kJ/Kg K and that of Pumice is 0.87 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 Pumice is impact resistant, pressure resistant.