[Rockhounds] Andri's mystery rocks

[edwardjwagner at bellsouth.net]

Dear Andri: In absence of location information , I have encountered two types of rocks/minerals that appear similarly to what you have. 
The first is specular hematite from Graves Mtn Mine in Lincoln Co. GA, about 40 miles N of Augusta.  Although pieces are scattered around the area, when one walks around the acid lake, the sides are compact hematite, often with colorful irridescent/specular  sheen, which means that the colors break up into a "rainbow"-like series of streaks.  This surface material resembles glazed red  bricks, or terracotta tiles in other aspects: the streak is red, the hardness is about a Mohs' 3, the compact interior contains "grains" within the mass. Due to the serious acidification  of the  runoff , if one collects from around a gully that feeds into the lake, one can observe the color change on the surfaces. Also, there is a certain amount of manganese in the area, which  when oxidized, causes black coloring on the surfaces.  
In the  specimens which have been mined from the tunnels, the same general coloring exists (and I'm not referring to the commercial stuff which has been rendered into solid colors with fluoric acid), but one can observe boytoidal hematite, goethite, and vugs which show vesicles. That's one guess.
Then again, could it be a type of mixed rhyolite?
On the other hand, slag from steam boilers can be readily found at Ray Mica Mine in Yancey Co, NC. These were not formed "naturally", or by foundry activity, which did not exist on site. rather, blobs of the material, harder and more brittle, with mose gaseous interiors, like lava, are the product of the machinery used at the time, hence the name "Steam-shovel". Before compressed air and hydraulic machinery, heavy equipment was steam driven. A fire box, fueled by coal or wook, burned under a boiler, which used steam to power the pistons to drive the works, as in a locomotive. At the end of the work period (day or week), the machines were shut down, and the fireman would rake out the hot ashes or coals onto the ground, then dump whatever water was left in the boiler tank on top of them to prevent starting a forest fire. The heat would melt any dirt, rocks or ground material beneath, then the superheated water, obtained from local creeks, would be dumped on top of the ashes. Whatever minerals in water would react with the other material, and steam and gasses would percolate thru the top , creating a glassy mass.
Typically, slag is a real mix of material, but the pieces I've picked up at Ray Mine have a smooth top, and a rough underside, where sand, quartzite, feldspar and other hard particles have stuck to the hot stuff.  They often fool collectors, especially the newbies, and I have to tell them what it is, but add that is is collectible as a mining artifact, like spikes and pieces of chain found near the loading areas.
In response to mentioning slag along RR tracks, in industrial areas, cinders and slag were used as railroad ballast, as a cheap substitute for granite or other rock that had to be hauled, especially in industrial areas. Of course, the slag previously mentioned may have fallen off of open freight or mining cars, like a lot of other material transported in the same manner.
During the Korean War, my Father served in the US Navy, and my mother, brother and I liven in the town of Wharton ,Texas. I lived in the then expanding suburbs, and could walk about a mile to the local RR tracks, used to haul sulphur and other raw materials  east to the Houston refineries, about 60 miles to the northeast.  One of my school friends showed me how to find lumps of  the yellow crystallized stuff, which we sucked on. My grandparents and mother were not too enamored by my "discovery", and forbade me from going over there, in fear that something "bad" would happen to me. I suppose they meant getting crushed by a train. The point is, all types of minerals can be found along the RR Tracks, and not all of them are native; in fact, there is a lot of representation of what the RR is hauling.
And, since I've backed into the Texas thread, and my mother's family has been living there since 1853, I consider myself an adopted Texan. One comment that I've always heard (not so much since Alaska was admitted to the Union as a state), has been:"You can always tell a Texan, but you can't tell him much!"
At that, I'll definitely drop the thread, and I hope y'all will do the same. 
Sincerely, EJW
 

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