Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Jasperoid is a rare, peculiar type of metasomatic alteration of rocks
Discoverer
Unknown
Unknown
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From silica, the main mineral content of Jasperoid
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Color
Black to Grey, Dark Greenish - Grey
Black, Brown, Green, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Glassy or Pearly
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
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, Production of Glass and Ceramics, Serves as an Oil and Gas Reservoir rock
Medical Industry
-
Taken as a Supplement for Calcium or Magnesium
Antiquity Uses
Artifacts
Artifacts, Jewellery, Monuments, Sculpture
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
-
Features
Available in Lots of Colors and Patterns
Host Rock for Lead, Traps for subsurface fluids like Oil and Natural Gas., Zinc and Copper Deposits
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.
Jasperoid is a rare and peculiar type of metasomatic alteration of rocks. It is formed by extreme alteration of wall rocks within a shear zone which may occur in sediments, andesites, trachytes and basalts.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Clay Minerals, Pyrite, Quartz, Sulfides
Compound Content
Ca, Fe, Potassium Oxide, Potassium, Silicon Dioxide
NaCl, CaO, Carbon Dioxide, Magnesium Carbonate, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
-
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Less Porous
Luster
Greasy to Dull
Vitreous and Pearly
Specific Gravity
2.34-2.40
2.8-3
Transparency
Opaque
Transparent to Translucent
Density
-9999 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
China, India
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Morocco, Namibia
Europe
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
Austria, Italy, Romania, Spain, Switzerland
Deposits in Western Continents
North America
Canada, USA
Mexico, USA
South America
-
Brazil, Colombia
Deposits in Oceania Continent
Australia
-
New South Wales, Queensland, Yorke Peninsula