written by: Sonal Panse•edited by: Donna Cosmato•updated: 11/26/2010
Graves Mountain geology is interesting as a variety of different minerals are found here. These minerals were formed due to heat and pressure on the land mass during the continental shifts. The site is well-known to rock hunters, especially for its Rutile and Pyrophyllite minerals.
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Graves Mountain, which is situated in Lincoln County in Georgia, United States, has long been famous for its varied mineral deposits. Over twenty different types of minerals have been found here in varying amounts. In the 1800s, the mining possibilities attracted many prospectors and later the central part of the mountain was mined for kyanite. The mine is no longer in operation but given the Graves Mountain geology, the area is regularly frequented by rock hunters on the lookout for interesting minerals. Some of these minerals have been exposed to the surface due to erosion and weathering, and can be easily picked up, while others lie below the surface and need to be extracted using a pick-ax or a sledge hammer.
Geological History of Graves Mountain
But why does the Graves Mountain geology have such a varied character? The answer, geologists say, lies in the heat and pressure that the land mass was subjected to during the continental shifts. The continent broke up, drifted apart, collided and reformed and in the process produced metamorphic sedimentary and igneous rocks and brought about alterations in original minerals and gave rise to many new ones.
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Types of Minerals Found at Graves Mountain
As mentioned, the Graves Mountain geology is varied, and here are some of the minerals that have been found at the site -
Cacoxenite - Yellow fiber-like crystals.
Crandallite - White, chalky crystals
Dickite - Colorless mica-like plates.
Hematite, Goethite or Limonite – Iridescent, rainbow-colored rocks.
Pyrophyllite – Clear whitish, yellowish, grayish or greenish crystals.
Quartz - Milky or translucent blue crystals.
Quartzite - Light gray, hard, base rock.
Rutile – Shiny, reddish-black crystals with a metallic look.
Strengite - Pink crystals.
Sulfur crystals - Transparent yellow crystals
Variscite – Green or colorless crystals.
Woodhouseite – Light tan crystals.
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Rules and Safety Precautions for Collecting
If you are interested in collecting minerals at Graves Mountain, it will help to take a membership to a geology club. There are many such local clubs and they regularly arrange rock and mineral collecting trips to the Graves Mountain area for their members. Trips are generally arranged between September and May as summer months can be quite hot in Georgia.
Going along with folks who are knowledgeable about the Graves Mountain geology can make it easier to locate and identify the different types of rocks and minerals. It is important to know how to extract the minerals without damaging the crystals or causing any kind of accident. Obviously, you will need to follow certain commonsensical safety precautions at the site :
Wear safety glasses, hard hats, gloves and sensible footwear.
Use sunscreen, especially if you are going in the summer months.
Be careful when using tools such as chisels, sledge-hammers, pry bars and shovels.
Watch your step on the terrain, stay away from rock walls as these can be quite unstable, be alert to the possibility of loose rocks and boulders, and exercise caution when moving any rocks.
You may also want to read up on how to store and care for your rocks and minerals. For instance, hematite, which gets its iridescence due to the presence of iron, should not be washed or allowed in contact with water as this can make it lose its sparkle.
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The Georgia Mineral Society - http://www.gamineral.org/
PHOSPHATE MINERALS AT GRAVES MOUNTAIN, GEORGIA, By: Henry Barwood, Head, Mineral Resources Section, Indiana, Geological Survey, GMS Member - http://www.gamineral.org/gravesmt-hb.htm
Piedmont Geologic Province - http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-1162
Graves Mountain Mines, Graves Mountain, Lincoln Co., Georgia, USA - http://www.mindat.org/locdetailed-3719.html
Surface mining, By B. A. Kennedy, SME, 1990 - Technology & Engineering
American Rockhounds: Graves Mountain: Part One -http://www.youtube.com/watch?v=n57-JR4hKvg
American Rockhounds: Graves Mountain: Part Two - http://www.youtube.com/watch?v=A0n1ZZFval8
Minerals of Graves Mountains - http://commons.wikimedia.org/wiki/Category:Minerals_of_Graves_Mountain
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Goethite - Photo by Rob Lavinsky -http://commons.wikimedia.org/wiki/File:Goethite-38437.jpg and http://www.mindat.org/photo-38437.html
Rutile - Photo by Rob Lavinsky - http://commons.wikimedia.org/wiki/File:Rutile-22020.jpg and http://www.mindat.org/photo-22020.html
Pyrophyllite - Photo by Rob Lavinsky - http://commons.wikimedia.org/wiki/File:Pyrophyllite-157164.jpg and http://www.mindat.org/photo-157164.html