56 CORUNDUM, ITS OCCURRENCE AND DISTRIBUTION. 
northeastern part of Towns County, Ga., are corundum bearing. 
These rocks vary in composition from those that are a normal gneiss 
to those that contain no feklspar and can best be described as quartz- 
schist composed of quartz and biotite mica. Some portions of the 
rock are rich in garnet, others are ahnost entirely free from this min- 
eral, and occasionally there are also small bands of white quartzite. 
The rocks are distinctly laminated and are frequently intersected by 
granitic dikes some of which are coarsely crystallized and of a peg- 
matitic character. These dikes are often parallel with the bedding 
of the schists, although many of them cut irregularly through the 
schists. Where these dikes are parallel to the bedding of the schists, 
the laminated structure of the latter is much more apparent. The 
general strike of these crystalline rocks is about northeast and south- 
west and the dip is about 30° NW. 
Portions or bands of these schists are corundum bearing, l)ut they 
are irregularly defined and gradually merge into the normal rock. 
They have a relation to the normal schists similar to that of the garnet- 
bearing bands of a gneiss to' the normal gneiss in which they occur. 
Tliese bands are not veins in any sense of the word, but are simply 
portions of the same mass of crystalline rocks in which corundum 
occurs as a constituent of the rock. They vary in width from a foot 
or two to 12 or 15 feet, but in these wider bands the corundum-bearing 
portion is not continuous and is intercei)ted by streaks of barren rock 
and granitic dikes. The bands can be traced for a distance of 5 or 6 
miles in a northeast-southwest direction, sometimes outcropping con- 
tinuously for nearly a mile. There are at least two of these corundum- 
bearing bands which are parallel to each other and about 2 miles 
apart. The only variation that has been observed in them is in the 
percentage of corundum and garnet; otherwise they are identical. 
The amount of corundum is never large, and from determinations 
made on samples from various parts of the deposits it will not average 
over 2 to 3 per cent. 
The corundum occurs for the most part in small particles and frag- 
ments that have no regular shape and are of a gray, white, and bluish- 
white color or almost colorless. It is also in crystals Avhich vary in 
size from some that are very minute to some that are 2^ inches long 
and about one-half inch in diameter, and that are usually fairly well 
developed in the prism zone. Suggestions regarding the origin of 
the corundum in these schists are given on pages 96-97. 
Near Teltonville, Forsyth County, Ga., surface specimens of corun- 
dum have been found that evidently originated in the quartz-schists 
of that region. 
