Definition
Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorthosite, or a pyroxene-depleted relative of gabbro
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
History
Origin
-
-
Discoverer
Christian Leopold von Buch
Unknown
Etymology
From German Troklotit, from Greek trōktēs, a marine fish (taken to be trout)
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
-
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Phaneritic
Banded, Rough
Color
Dark Grey to Black
Black, Brown, Green, Grey, Red, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Veined and Shiny
Glassy or Pearly
Architecture
Interior Uses
Bathrooms, Countertops, Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration, Kitchens
Decorative Aggregates, Homes
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Medical Industry
-
-
Antiquity Uses
Artifacts, Jewellery, Monuments, Sculpture
Artifacts, Monuments
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Types
Ultramafic rock
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Features
Smooth to touch
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Present
Formation
Troctolite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.
Composition
Mineral Content
Augite, Olivine, Plagioclase, Pyroxene
Quartz, Silicon
Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Silicon Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Mechanical Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Chemical Erosion
Physical Properties
Hardness
76.5-7
1
7
👆🏻
Grain Size
Coarse Grained
Very fine-grained
Fracture
Conchoidal
Uneven, Splintery or Conchoidal
Streak
Black
White
Porosity
Highly Porous
Highly Porous
Luster
-
Waxy and Dull
Compressive Strength
225.00 N/mm2450.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
1.6
1.5
Specific Gravity
2.86-2.872.5-2.8
0
8.4
👆🏻
Transparency
Opaque
Translucent to Opaque
Density
2.7-3.3 g/cm32.7 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K0.74 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
South Africa
Kenya, Morocco, South Africa, Tanzania
Europe
Germany, Greece, Italy, Scotland, Turkey
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
Greenland
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil, Colombia, Venezuela
Bolivia, Brazil
Deposits in Oceania Continent
Australia
New Zealand, Queensland
New South Wales, Queensland, South Australia, Western Australia