THE GOLD OF THAT LAND: Biblical Minerals & Rocks  


 

Appendix 4

Rock Identification Charts

 

Table 4: Field classification of igneous rocks

Category

Principal

minerals

%

silica

% dark

minerals

phaneritic

aphanitic

glassy

Felsic

>10% quartz

>2/3 K-feldspar

72

10

Granite

Rhyolite

Obsidian

 

 

 

<10% quartz

> 2/3 K-feldspar

59

15

Syenite

Trachyte

1/3 - 2/3 feldspars,  ~ 50/50 K-feldspar & plagioclase

55

20

Monzonite

Latite

Intermediate

>10% quartz

>10% K-feldspar

>2/3 Na-feldspar

66

20

Granodiorite

Dacite

<10% quartz

<10% K-feldspar

>2/3 Na-feldspar

57

25

Diorite

Andesite

 

Mafic

<10% quartz       >2/3 Ca-feldspar

48

50

Gabbro Anorthosite

Basalt

Tachylite

Ultramafic

0% quartz

mafic minerals only

41

95

Pyroxenite  Peridotite     Dunite

 

 

 

 

 

Table 5: Field classification of metamorphic rocks

 

REGIONAL METAMORPHISM

Original

rock

Metamorphic rank

     Low                                                                                       High

chlorite

biotite

almandite

staurolite

sillimanite

Metamorphic rock

Shale

Slate

Biotite phyllite

Biotite-garnet phyllite

Biotite-garnet-staurolite schist

Sillimanite schist or gneiss

Argillaceous sandstone

Micaceous sandstone

Quartz-mica schist

Quartz-mica-garnet schist or gneiss

Quartz sandstone

Quartzite

Limestone,

Dolomite

Limestone

Dolomite

Marble

Basalt

Greenschist:

chlorite-epidote-albite schists

Albite-epidote amphibolite

Amphibolite

Granite

Granite

Granite gneiss or Migmatite

Rhyolite

Rhyolite

Biotite schist or Gneiss

 

CONTACT METAMORPHISM

Sandstone

Quartzite

Limestone, Dolomite

Marble

Serpentinite, Soapstone

Argillaceous sandstone

Hornfels

Granulite

Coal

Anthracite

Graphite

Basic igneous rocks

Serpentinite, Soapstone

 

 

 

Table 6: Field classification of sedimentary rocks

 

 

 

CLASTIC: made of particles of older rocks and their alteration products

 

Texture

Grain size

Name

 

Detrital

Clastic

Granule or larger, >2mm

Conglomerate (rounded)

Breccia (angular grains)

 

Sand, 0.05 2mm diam

Sandstone

 

Silt, 0.05 0.005mm

Siltstone, loess

 

Clay, < 0.005 mm

Mudstone, shale

 

 

NON-CLASTIC: made of minerals deposited from solution

 

Origin

Texture

Composition

Name

 

Inorganic & organic

Crystalline & clastic

Calcite, CaCO3

Limestones, chalk, travertine, tufa

 

Inorganic

Crystalline

Dolomite,                   CaMg(CO3)2

Dolomite

 

Inorganic

Crystalline

Halite, NaCl

Rock salt

 

Inorganic

Crystalline

Gypsum, CaSO4.2H2O; anhydrite, CaSO4

Gypsum, anhydrite

 

Inorganic & organic

Crystalline & clastic

Silica, SiO2

Chert, flint, novaculite, diatomite

 

Organic

Clastic & crystalline

Carbonized plant remains

Lignite, coal, anthracite

 

Organic

Crystalline

Iron oxides & hydroxides

Banded iron ores

 


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