Definition
Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous Rock
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature
Discoverer
Unknown
Edgar Bailey
Etymology
From the locality in Essex County, Massachusetts,US
From French schiste, Greek skhistos i.e. split
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Plutonic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Granular
Foliated
Color
Dark Grey to Black
Blue, Bluish - Grey, Purple, Shades of Blue
Durability
Durable
Durable
Appearance
Banded
Dull and Banded
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Commemorative Tablets, Jewelry, Sea Defence, Tombstones
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones
Types
Not Available
Not Available
Features
Is one of the oldest rock, Smooth to touch
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Formation
Essexite is a type of igneous rock, which is usually dark grey to black plutonic rock. For the formation of essexite, suitable magma with exact composition of K, Ba, Rb, Cs, Sr should be produced.
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.
Mineral Content
Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz
Compound Content
Aluminium Oxide, Ba, Ca, Cs, Potassium, Rb, Sodium, Sr
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering
Mechanical Weathering
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine to Medium Grained
Fracture
Conchoidal
Conchoidal
Streak
Black
White to Grey
Porosity
Highly Porous
Highly Porous
Luster
Not Available
Dull
Cleavage
Not Available
Slaty
Specific Gravity
Not Available
3-3.2
Transparency
Opaque
Opaque
Density
Not Available
2.8-2.9 g/cm3
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
India, Russia
Japan, Turkey
Africa
South Africa
Egypt, Ethiopia, South Africa
Europe
Germany, Greece, Italy, Scotland, Turkey
France, Greece, Iceland
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil, Colombia, Venezuela
Not Yet Found
Deposits in Oceania Continent
Australia
New Zealand, Queensland
New Zealand