Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Laterite rock is a type of Sedimentary rock which is rich in iron and aluminium, formed in hot and wet tropical areas
Discoverer
Unknown
Francis Buchanan-Hamilton
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From Latin later brick, tile + -ite1
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Earthy, Massive, Porphyritic
Color
Black, Brown, Green, Grey, Red, Rust, White
Brown, Buff, Red
Durability
Durable
Durable
Appearance
Dull
Rough and Banded
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Construction Aggregate
Cobblestones, for Road Aggregate, Landscaping, Roadstone
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Gemstone, Jewelry
An Oil and Gas Reservoir, Source of bauxite, Used in aquariums
Types
Rhomb Porphyry
Laterite
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Is one of the oldest rock, Very fine grained 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.
Laterite is a type of sedimentary rock which is generally a reddish weathering product of basalt.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Aluminum Oxides, Biotite, Hematite, Hornblade, Iron Oxides, Manganese Oxides, Micas, Muscovite or Illite, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
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
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Irregular
Conchoidal
Porosity
Less Porous
Highly Porous
Specific Gravity
2.5-4
-9999
Transparency
Translucent to Opaque
Opaque
Density
2.5-2.52 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
India
Africa
Egypt, Ethiopia, Ghana, South Africa
East Africa, Western Africa
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
England, Romania, Scotland
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
Canada, USA
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
-
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
Central Australia, Western Australia