Definition
Shonkinite is a rare, dark-coloured and intrusive igneous rock which contains augite and orthoclase feldspar as its primary constituents
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Discoverer
Unknown
Unknown
Etymology
From the name of Shonkin Sag ranges in the Highwood Mountains of north-central Montana, US
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, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy
Banded, Rough
Color
Brown, Buff, Cream, Green, Grey, Pink, White
Black, Brown, Green, Grey, Red, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Banded and Foilated
Glassy or Pearly
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Types
Not Available
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Used
Not Yet Used
Formation
Shonkinites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.
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.
Mineral Content
Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz
Quartz, Silicon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion, Water Erosion
Chemical Erosion
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Fracture
Not Available
Uneven, Splintery or Conchoidal
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Waxy and Dull
Cleavage
Perfect
Non-Existent
Toughness
Not Available
1.5
Specific Gravity
2.6-2.7
2.5-2.8
Transparency
Opaque
Translucent to Opaque
Density
2.6-2.8 g/cm3
2.7 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Kenya, Morocco, South Africa, Tanzania
Europe
Bulgaria, England, Germany, Norway, Romania, Switzerland
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
Not Yet Found
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
USA
Canada, Mexico, USA
South America
Brazil, Chile
Bolivia, Brazil
Deposits in Oceania Continent
Australia
New Zealand, Queensland, South Australia, Western Australia
New South Wales, Queensland, South Australia, Western Australia