Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Kimberlite is a rare, blue-tinged, coarse-grained intrusive igneous rock, which sometimes contains diamonds and is mostly found in South Africa and Siberia.
Origin
USA
Kimberley, South Africa
Discoverer
Unknown
John W. Judd
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From Kimberley + -ite, from the name of the South African town of Kimberley where the rock was first found.
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
Texture
Earthy
Porphyritic
Color
Black to Grey, Dark Greenish - Grey
Black, Bluish - Grey, Brown, Dark Greenish - Grey, Green, Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Dull and Banded
Interior Uses
Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
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
Medical Industry
-
Taken as a Supplement for Calcium or Magnesium
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Creating Artwork
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO)
Types
Intermediate volcanic rock
Basaltic Kimberlites and Micaceous Kimberlites
Features
Available in Lots of Colors and Patterns
Always found as volcanic pipes over deep continental crust, Host rock for Diamond, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Formation
Rhyodacite 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.
Kimberlite is an igneous rock and is the main source of diamonds. Its formation takes place deep beneath the Earth’s surface between 150 to 450 kilometres, and are erupted rapidly and violently.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Garnet, Olivine, Phlogopite, Pyroxene
Compound Content
Ca, Fe, Potassium Oxide, Potassium, Silicon Dioxide
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact 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, 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 to Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Very Less Porous
Luster
Greasy to Dull
Subvitreous to Dull
Specific Gravity
2.34-2.40
2.86-2.87
Transparency
Opaque
Translucent to Opaque
Density
-9999 g/cm3
2.95-2.96 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Russia
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Angola, Botswana, Cameroon, Ethiopia, South Africa
Europe
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
England, Hungary, Iceland, United Kingdom
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
-
Argentina, Colombia, Ecuador
Deposits in Oceania Continent
Australia
-
New South Wales, New Zealand, South Australia, Western Australia