Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Diamictite is a sedimentary rock that consists of non-sorted to poorly sorted terrigenous sediment containing particles that range in size from clay to boulders, suspended in a matrix of mudstone or sandstone
Origin
Romania and Moldova, Europe
Southern Mongolia
Discoverer
Unknown
Unknown
Etymology
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
From Greek dia through and meiktós or mixed
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Brown, Buff
Durability
Durable
Durable
Appearance
Vesicular
Banded
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping, Roadstone
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Commemorative Tablets, Creating Artwork
Commemorative Tablets, Creating Artwork, Production of Lime
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Bedded Diamictite and Laminated Diamictite
Features
Host Rock for Lead, Is one of the oldest rock
Host Rock for Lead, Is one of the oldest rock
Archaeological Significance
Formation
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Diamictite is unevenly sorted terrigenous, non-calcareous sedimentary rock which forms due to weathering of mudstone and sandstone.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Calcite, Clay, Feldspar, Micas, Quartz
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
-
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Conchoidal
Conchoidal to Uneven
Streak
White
Light to dark brown
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Grainy, Pearly and Vitreous
Specific Gravity
2.86-2.87
4.3-5.0
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
2.2-2.35 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
-
China, India, Kazakhstan, Mongolia, Russia
Africa
-
Namibia, Nigeria, South Africa
Europe
France, Greece, Romania, Scotland, Spain
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New South Wales, New Zealand