Definition
Jaspillite is an iron rich chemically formed rock which is common in banded iron formation rocks
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Origin
Western Australia, Minnesota
Egypt
Discoverer
Unknown
Unknown
Etymology
From Jaspilite (Mineral), a compact siliceous rock which resembles jasper
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Banded, Trellis
Porphyritic
Color
Red, Reddish Brown
Black, Brown, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Appearance
Banded and Glassy
Dull
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Facing Stone, Garden Decoration, Paving Stone
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Construction Aggregate
Antiquity Uses
Artifacts, Jewellery, Monuments
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Jewelry
Creating Artwork, Gemstone, Jewelry
Types
Algoma-type , Lake Superior-type and Superior-type
Rhomb Porphyry
Features
Is one of the oldest rock
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Formation
Jaspillite is a type of sedimentary rock which is formed by the compaction and sedimentation of pieces of broken or weathered rocks and minerals.
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
Coesite, Quartz, Sand
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, 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
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Large and Coarse Grained
Fine Grained
Fracture
Conchoidal
Irregular
Porosity
Very Less Porous
Less Porous
Specific Gravity
5.0-5.3
2.5-4
Transparency
Translucent to Opaque
Translucent to Opaque
Density
0-5.7 g/cm3
2.5-2.52 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Russia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
-
Egypt, Ethiopia, Ghana, South Africa
Europe
Ukraine
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
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
Western Australia
New South Wales, New Zealand, Western Australia