Comendite

Pegmatite

Comendite and Pegmatite

Comendite

Pegmatite

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Definition

Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite

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

History

Origin

Italy

Discoverer

Unknown

R. J. Hauy

Etymology

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Plutonic

Other Categories

Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Porphyritic

Pegmatitic

Color

Blue, Bluish - Grey

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Foliated

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

As Building Stone, As Facing Stone, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar

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

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers

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

Types

Rhyolite

Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite

Features

Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

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

Composition

Mineral Content

Albite, Amphibole, Quartz

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

Compound Content

Al, Fe, Potassium Oxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Water Erosion

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

Properties

Physical Properties

Hardness

6-77

1 7

👆🏻

Grain Size

Medium Grained

Medium to Coarse Grained

Fracture

Pervasive

Conchoidal

Streak

Bluish Black

White

Porosity

Highly Porous

Less Porous

Luster

Dull

Grainy, Pearly and Vitreous

Compressive Strength

92.40 N/mm²178.54 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

2.382.6-2.63

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

-9999 g/cm³2.6-2.65 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

China

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

Africa

East Africa

South Africa

Europe

Italy

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

Others

Deposits in Western Continents

North America

Canada

South America

Brazil

Deposits in Oceania Continent

Australia

Queensland

New South Wales, Queensland, South Australia, Western Australia

All about Comendite and Pegmatite Properties

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