Definition
Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
Origin
Germany
New Zealand
Discoverer
Christian Leopold von Buch
Unknown
Etymology
From Latin glaber bare, smooth, bald
From Greek mulōn mill + -ite
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Phaneritic
Foliated
Color
Dark Grey to Black
Black to Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Veined and Shiny
Dull, Banded and Foilated
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
for Road Aggregate, Landscaping, Roadstone
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Commercial Uses
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Creating Artwork, Gemstone, Jewelry
Types
Anorthosite Gabbro and Norite Gabbro
Blastomylonites, Ultramylonites and Phyllonites
Features
Smooth to touch
Surfaces are often shiny
Archaeological Significance
Formation
Gabbro, a mafic rock, forms due to cooling and crystallization of magma underneath Earth's surface.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Mineral Content
Augite, Olivine, Plagioclase, Pyroxene
Porphyroblasts
Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Types of Metamorphism
Impact Metamorphism
-
Types of Weathering
Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Grain Size
Coarse Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Highly Porous
Specific Gravity
2.86-2.87
2.97-3.05
Transparency
Opaque
Opaque
Density
2.7-3.3 g/cm3
2.6-4.8 g/cm3
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
India, Russia
China, India, Indonesia, Saudi Arabia, South Korea
Africa
South Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Europe
Germany, Greece, Italy, Scotland, Turkey
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil, Colombia, Venezuela
-
Deposits in Oceania Continent
Australia
New Zealand, Queensland
Central Australia, Western Australia