Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Origin
Romania and Moldova, Europe
Hawaii Islands
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 pikros bitter + -ite, 19th century
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Earthy, Rough
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
Durability
Durable
Durable
Appearance
Vesicular
Rough and Shiny
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Commemorative Tablets, Creating Artwork
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Oceanite
Features
Host Rock for Lead, Is one of the oldest rock
Host Rock for Lead
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
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
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.
Picrite 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.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Biotite, Olivine, Plagioclase, Pyrrhotite
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Al, CaO, Carbon Dioxide, Mg, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Uneven
Streak
White
White, Greenish White or Grey
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Subvitreous to Dull
Compressive Strength
Not Available
Cleavage
Perfect
Imperfect
Toughness
Not Available
2.1
Specific Gravity
2.86-2.87
2.75-2.92
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
1.5-2.5 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Not Yet Found
India, Russia
Africa
Not Yet Found
South Africa
Europe
France, Greece, Romania, Scotland, Spain
Iceland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
Not Yet Found
All about Dacite and Picrite Properties
Know all about Dacite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite and Picrite belong to Igneous Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Picrite is Earthy, Rough. Dacite appears Vesicular and Picrite appears Rough and Shiny. The luster of Dacite and Picrite is subvitreous to dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).