Blueschist

Dacite

Blueschist and Dacite

Blueschist

Dacite

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Definition

Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature

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

History

Origin

USA

Romania and Moldova, Europe

Discoverer

Edgar Bailey

Unknown

Etymology

From French schiste, Greek skhistos i.e. split

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Foliated

Aphanitic to Porphyritic

Color

Blue, Bluish - Grey, Purple, Shades of Blue

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Banded

Vesicular

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

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

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones

Commemorative Tablets, Creating Artwork

Types

Metamorphic rock

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Features

Has High structural resistance against erosion and climate, Very fine grained rock

Host Rock for Lead, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.

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

Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz

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

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Mechanical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

3.5-42-2.25

1 7

👆🏻

Grain Size

Fine to Medium Grained

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White to Grey

White

Porosity

Highly Porous

Less Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

220.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Perfect

Toughness

1.5

Specific Gravity

3-3.22.86-2.87

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.8-2.9 g/cm³2.77-2.771 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan, Turkey

Africa

Egypt, Ethiopia, South Africa

Europe

France, Greece, Iceland

France, Greece, Romania, Scotland, Spain

Others

Deposits in Western Continents

North America

USA

South America

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

Deposits in Oceania Continent

Australia

New Zealand

New Zealand, South Australia, Western Australia

All about Blueschist and Dacite Properties

Know all about Blueschist and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Blueschist belongs to Metamorphic Rocks while Dacite belongs to Igneous Rocks.Texture of Blueschist is Foliated whereas that of Dacite is Aphanitic to Porphyritic. Blueschist appears Dull and Banded and Dacite appears Vesicular. The luster of Blueschist is dull while that of Dacite is subvitreous to dull. Blueschist is available in blue, bluish - grey, purple, shades of blue colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Blueschist and Dacite are cemetery markers, commemorative tablets, creating artwork, curling, tombstones.