Pegmatite

Dacite

Pegmatite and Dacite

Pegmatite

Dacite

Add ⊕

Definition

Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals

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

History

Origin

Romania and Moldova, Europe

Discoverer

R. J. Hauy

Unknown

Etymology

From Greek pegma, pegmat which means- thing joined together + -ite

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

Plutonic

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Pegmatitic

Aphanitic to Porphyritic

Color

Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, 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

Layered, Banded, Veined and Shiny

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Paving Stone

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping

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

Medical Industry

Antiquity Uses

Artifacts, Sculpture, Small Figurines

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz

Commemorative Tablets, Creating Artwork

Types

Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Features

Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz

Host Rock for Lead, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.

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

Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz

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

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of 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

72-2.25

1 7

👆🏻

Grain Size

Medium to Coarse Grained

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Less Porous

Luster

Grainy, Pearly and Vitreous

Subvitreous to Dull

Compressive Strength

178.54 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

2.6-2.632.86-2.87

0 8.4

👆🏻

Transparency

Translucent to Opaque

Translucent

Density

2.6-2.65 g/cm³2.77-2.771 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea

Africa

South Africa

Europe

Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine

France, Greece, Romania, Scotland, Spain

Others

Deposits in Western Continents

North America

Canada

USA

South America

Brazil

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

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

New Zealand, South Australia, Western Australia

All about Pegmatite and Dacite Properties

Know all about Pegmatite and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Pegmatite and Dacite belong to Igneous Rocks.Texture of Pegmatite is Pegmatitic whereas that of Dacite is Aphanitic to Porphyritic. Pegmatite appears Layered, Banded, Veined and Shiny and Dacite appears Vesicular. The luster of Pegmatite is grainy, pearly and vitreous while that of Dacite is subvitreous to dull. Pegmatite is available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Pegmatite are creating artwork, jewelry, source of corundum, tourmalines, beryls and topaz and that of Dacite are commemorative tablets, creating artwork.