66 THE POPULAR SCIENCE MONTHLY. 



sheet, we can get the garnet-plate set in mica, and it makes a 

 specimen well worth preserving. Less frequently one finds a 

 thin layer of quartz imprisoned between the mica, or a thin layer 

 of the transparent glassy feldspar known as sanidin. Sometimes 

 the mica itself is microscopically striated, and plays queer tricks 

 with the light, giving iridescent films that might easily be mis- 

 taken for soap-bubbles. 



But the feldspar is the most promising matrix for the mineral 

 hunter. At the Cloudland mine it is well penetrated with the 

 greenish, yellowish, and bluish hexagonal prisms of the beryl. 

 The precious form of this mineral, the emerald, is seldom or never 

 found in the mica mines. There is, however, an intermediate 

 variety known as the aqua marine, which occurs in the mines 

 around Spruce Pine, and is somewhat esteemed as a gem. As the 

 name indicates, it is of a light sea-green color. It is perfectly 

 transparent, and when well cut makes a quiet but really beauti- 

 ful gem-stone. Clear crystals of aqua marine are exceedingly 

 rare. It comes commonly as a part of the opaque crystal of 

 beryl. 



Intimately associated with the beryl are plentiful sprinklings 

 of blood-red garnets, and the two colorings against the pure 

 white background of the feldspar make a very effective combina- 

 tion. Garnets are generously distributed in nearly all the mica 

 mines, and add much to the beauty of these mineral masses. One 

 day at the Cloudland mine, a large mass of feldspar was blown 

 down, and there in the center of the white and standing face of 

 the vein was a blood-red spot at least six or seven inches in 

 diameter. A giant garnet had been cut squarely in two by the 

 blast, and the blood-red spot was a cross-section of what re- 

 mained. 



In other mines, such as the Tolly Bend in Yancey County, the 

 white feldspar is occasionally covered with patches of dainty 

 pink. It is the mineral rhodonite, a silicate of manganese, and is 

 as delicate as a peach-blow vase. 



There are also other accessory minerals which are less strik- 

 ing in appearance, but of greater scientific interest on account of 

 their rarity. Such are euraninite, gummite, columbite, and samar- 

 skite, containing the rare metals uranium, columbium, yttrium, 

 tungsten, tantalum, and their allies, which are curiosities even to 

 the chemist. At Spruce Pine, one gets excellent specimens of 

 uraninite, the oxide of uranium. It is a heavy black mineral 

 with a frequent orange-yellow coating of another uranium com- 

 pound, gummite. The miners take considerable interest in find- 

 ing the mineral, as it is worth something like a couple of dollars 

 a pound, and it takes a very small quantity to make a pound. 

 The oxides of the metal are used to produce black and yellow col- 



