Picrite

Dacite

Picrite and Dacite

Picrite

Dacite

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Definition

Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine

Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite

History

Origin

Hawaii Islands

Romania and Moldova, Europe

Discoverer

Unknown

Etymology

From Greek pikros bitter + -ite, 19th century

From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Earthy, Rough

Aphanitic to Porphyritic

Color

Black, Brown, Green, Grey, Pink, White, Yellow

Bluish - Grey, Brown, Grey, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Rough and Shiny

Vesicular

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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.

As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)

Commemorative Tablets, Creating Artwork

Types

Oceanite

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Features

Host Rock for Lead

Host Rock for Lead, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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.

Composition

Mineral Content

Biotite, Olivine, Plagioclase, Pyrrhotite

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon

Compound Content

Al, CaO, Carbon Dioxide, Mg, MgO

Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

6.82-2.25

1 7

👆🏻

Grain Size

Fine Grained

Medium to Fine Coarse Grained

Fracture

Uneven

Conchoidal

Streak

White, Greenish White or Grey

White

Porosity

Less Porous

Luster

Subvitreous to Dull

Compressive Strength

189.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

2.75-2.922.86-2.87

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

1.5-2.5 g/cm³2.77-2.771 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Africa

South Africa

Europe

Iceland

France, Greece, Romania, Scotland, Spain

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Brazil

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

All about Picrite and Dacite Properties

Know all about Picrite and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Dacite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Dacite is Aphanitic to Porphyritic. Picrite appears Rough and Shiny and Dacite appears Vesicular. The luster of Picrite and Dacite is subvitreous to dull. Picrite is available in black, brown, green, grey, pink, white, yellow colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Dacite are commemorative tablets, creating artwork.