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May 15, 2016 Weekly Geology Guess

May 15, 2016
Greetings from the Bluff Park   Porch, way up yonder on Shades Mountain (1,109′) in Alabama:

With my discussion on Alabama Geology, I have gotten the geologic cart before the horse.  I have not included a basic discussion regarding rocks and all the various kinds of sedimentary, metamorphic, and igneous rocks.

We will continue with Metamorphic Rocks (2).


Minerals and Rocks – The Good Life from the Ground
“If it ain’t grown, it has to be mined”
Metamorphic Rocks


>    This is one of the best and simple explanations of Metamorphic Rocks.

Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means “change in form”.[1] The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (1500 bars),[2] causing profound physical and/or chemical change. The protolith may be a sedimentary rock, an igneous rock or another older metamorphic rock.”  Wikipedia

There are two basic types of metamorphic rocks.

Foliated metamorphic rocks such as gneiss, phyllite, schist, and slate.   These have a layered or banded appearance that is produced by exposure to heat and directed pressure. 

Non-foliated metamorphic rocks such as hornfels, marble, quartzite, and novaculite
For a more in depth review of metamorphic rocks, go to

>    This week I will forgo the formal subdivision of metamorphic rocks and include some to the minerals that have been mined from Alabama Metamorphic Rocks.

Copper The Stone Hill mine (also known as the Woods mine) in Cleburne County, Alabama was discovered in 1874, and worked 1874 to 1879, and 1896 to 1899. Production was hampered by poor transportation. The ore is massive and disseminated sulfides in hornblende schist of Precambrian or Paleozoic age. Principal ore minerals are chalcopyrite (CuFeS2) and sphalerite, which occur with pyrrhotite, pyrite, and quartz.


Gold has been reported in Clay, Randolph, Cleburne, Talladega, Tallapoosa, Coosa, and Chilton counties in more than 100 prospects and mines either in metamorphic or igneous rocks. Goldville Mine

Graphite is a crystalline form of carbon

“The mineral is particularly abundant in Clay, Coosa, and southeastern Chilton counties, and the graphite-rich rocks within these counties form one of the largest graphite deposits in the United States.”

It has many-many uses to include pencils, refractories, batteries, steelmaking, expanded graphite, brake linings, foundry facings and lubricants.

Kyanite is a neosilicate, Al2SiO5.Kyanite is used primarily in refractory and ceramic products, including porcelain plumbing fixtures and dishware. It is also used in electronics, electrical insulators and abrasives.

Magnetite is a mineral and one of the three common naturally-occurring oxides of iron. Its chemical formula is Fe3O4

Magnetite is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself.

Sylacauga, Alabama Marble:  Some of the finest white marble comes from the Sylacauga Marble.  A lot of the “Fine Italian Marble” comes from Sylacauga.  The source of the marble are the limestones and dolomite of Cambrian-Ordovician Age to the North of Sylacauga.Limestone from these quarries are used as a food grade additive, construction, sculpture, polished decorative stone.

Muscovite (also known as common mica, isinglass, or potash mica[4]) is a phyllosilicate mineral of aluminium and potassium with formula KAl2(AlSi3O10)(F,OH)2, or (KF)2(Al2O3)3(SiO2)6(H2O).
“Mica-bearing rocks have been mined extensively in Randolph, Cleburne, Clay, Coosa, and Tallapoosa counties. Commercial mining of muscovite sheet mica deposits in Alabama began in 1870 at the Pinetucky No. 1 mine in Randolph County. Scrap or flake mica is used by industry in dry-, wet-, or micronized-ground form for use in construction materials such as roofing, shingles, wallboard, and paint.
Pyrite or iron pyrite, also known as fool’s gold, is an iron sulfide with the chemical formula FeS2.
Pyrite deposits in the Hillabee Greenstone geologic formation in the vicinity of Pyriton, Clay County, were first mined in the 1850s by mining companies for the production of sulphur acid and elemental sulfur.
Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone.
Quartzite uses include railroad and road ballast, decorative stone, ferrosilicon, industrial silica sand, silicon and silicon carbide.
Talc (hydrated magnesium silicate) occurs in association with metamorphosed dolomite near Winterboro, Talladega County.
Talc is used primarily in talcum powder, ceramics, cosmetics, paints, and construction materials.
Other minerals include amphiboles, amethyst, andalusite, beryl (emerald), apatite, calcite, fluorite, gypsum, ilmenite, magnetite, monazite, niter, onyx, opal, quartz (agate), rutile, staurolite, tourmaline, turquoise, and wavellite.
References include:
–    Wikipedia
Attached is a handy guide to rocks by the USGS (US Geological Survey).  Simple in terms of Petrology, but still detailed.  R


Editors Note:  It is the intent of this site to keep this discussion as simple as possible, so as to educate the interested general public and not to discuss with the geology crowd the latest geologic theories and nuances.  Thanks, R


“No copyright infringement intended.
The rights belong to their respective owners”

Copyright Disclaimer: Under Section 107 of the Copyright Act 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use.

Author’s Request:  If you see any pictures that you know the source and photographer, let me know immediately.  Thanks!  R

Images have been searched by TinEye Reverse Image Search.


Next week we will venture into the igneous rock of Alabama

Have A Great Week!

Note:  I have upgraded my WordPress web site service to premium.  So, I am still trying to figure out all of the bells and whistles. Thanks  R

AL Geo. Map, Piedmont

Alabama Geology Map of the Piedmont

Chalcopyrite. Ducktown District, Polk Co. TN.

Chalcopyrite. Ducktown District, Polk Co. TN.

AL. Piedmont - Metamorphic. Oldest Gold Mine in AL, Dec09. by R. McDaniel

AL. Piedmont – Metamorphic. Oldest Gold Mine in AL, Dec09. by R. McDaniel

AL Graphitic Schist.

AL Graphitic Schist.

Alabama Graphite Co.

Alabama Graphite Co.

AL Minerals.  Kyanite.  Turkey Heaven, Cleburne Co. AL.

AL Minerals. Kyanite. Turkey Heaven, Cleburne Co. AL.

Magnetite, AL. by Lewis Dean

Magnetite, AL. by Lewis Dean

Marble.  AGS, Sylacauga, AL. by R. McDaniel

Marble. AGS, Sylacauga, AL. by R. McDaniel





Pyrite Crystals, 31mm. Navajun, Rioja, Spain. 07-24-2009. by CarlesMiilan

Pyrite Crystals, 31mm. Navajun, Rioja, Spain. 07-24-2009. by CarlesMiilan



Talc - Soapstone,

Talc – Soapstone,

Talc. 07-09-2005. Sanao. .

Talc. 07-09-2005. Sanao. .

Talcum Powder. unknown

Talcum Powder. unknown

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