Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Discoverer
Unknown
Unknown
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From German Grauwacke, from grau grey + wacke
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Black to Grey, Dark Greenish - Grey
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Floor Tiles, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing, Whetstones
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Creating Artwork
As armour rock for sea walls, Petroleum reservoirs, Sea Defence, Tombstones
Types
Not Available
Not Available
Features
Available in Lots of Colors and Patterns
Available in Lots of Colors and Patterns, Generally rough to touch, Non-vesicular, Veined
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Used
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.
Graywacke rock is a type of sedimentary rock, which is also known as immature sandstone, which is indurated, dark grey and consisting of poorly sorted angular to sub-angular, sand-sized grains.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Augite, Biotite, Calcite, Chlorite, Clay, Clay Minerals, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz
Compound Content
Ca, Fe, Potassium Oxide, NA, Potassium, Silicon Dioxide
Aluminium Oxide, NaCl, CaO, Chromium(III) Oxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, 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
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Coastal Erosion, Sea Erosion, Wind Erosion
Grain Size
Fine Grained
Angular and Fine
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Highly Porous
Luster
Greasy to Dull
Dull
Compressive Strength
Not Available
Cleavage
Not Available
Perfect
Specific Gravity
2.34-2.40
2.2-2.8
Transparency
Opaque
Opaque
Density
Not Available
2.6-2.61 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Namibia, Nigeria, South Africa
Europe
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Not Yet Found
Brazil
Deposits in Oceania Continent
Australia
Not Yet Found
New South Wales, New Zealand
All about Rhyodacite and Greywacke Properties
Know all about Rhyodacite and Greywacke properties here. All properties of rocks are important as they define the type of rock and its application. Rhyodacite belongs to Igneous Rocks while Greywacke belongs to Sedimentary Rocks.Texture of Rhyodacite is Earthy whereas that of Greywacke is Clastic. Rhyodacite appears Skeletal and Greywacke appears Dull. The luster of Rhyodacite is greasy to dull while that of Greywacke is dull. Rhyodacite is available in black to grey, dark greenish - grey colors whereas Greywacke is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Rhyodacite are cemetery markers, creating artwork and that of Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones.