Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Oolite is a sedimentary rock formed from ooids, spherical grains which are composed of concentric layers of calcite
Discoverer
Unknown
William Smith
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From oo- + -lite, after German Oolit. A rock consisting of fine grains of carbonate of lime
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy
Clastic or Non-Clastic
Color
Black to Grey, Dark Greenish - Grey
Black, Blue, Brown, Cream, Green, Grey, Pink, Red, Silver, White, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Rounded and Rough
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
-
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Cement Manufacture, Cobblestones, Landscaping
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Jewelry, Used in aquariums
Types
Intermediate volcanic rock
Pisolitic Oolite and Oncolitic Oolite
Features
Available in Lots of Colors and Patterns
Available in lots of colors, Generally rough to touch, Very fine grained rock
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.
Oolites form when layers of calcite are deposited around a sand grain or fossil piece and are rolled around in calm water, which makes them round.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Calcite, Chert, Clay, Dolomite, Quartz, Sand, Silt
Compound Content
Ca, Fe, Potassium Oxide, Potassium, Silicon Dioxide
Aluminium Oxide, Ca, NaCl, CaO, Iron(III) Oxide, FeO, MgO
Types of 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
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Less Porous
Luster
Greasy to Dull
Pearly to Shiny
Specific Gravity
2.34-2.40
-9999
Transparency
Opaque
Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
United Kingdom
Deposits in Western Continents
North America
Canada, USA
USA
Deposits in Oceania Continent
Australia
-
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula