Agate— Physical Properties and Origin 17 
The methods above described will indicate the 
principal ones used in coloring agates. By modifications 
of these methods other colors can be obtained. Ani- 
line dyes can be used, but they are likely to fade in 
a short time. An illustration of a number of colors 
artificially given to a single section of agate is shown 
in Plate VII. 
The coloring of agate, like the cutting of agate, is 
carried on chiefly in Germany. In the localities de- 
voted to this industry it is said to be to a considerable 
extent a household occupation, the processes often 
being carried on in home kitchens. 
Cutting and Polishing of Agates 
The industry of cutting and polishing of agates is 
now carried on chiefly in the vicinity of Idar and 
Oberstein, two towns located on the Idar and Nahe 
rivers in southwestern Germany. Agates were form- 
erly abundant in this region and the art of cutting 
and polishing them was developed to such an extent 
that when the local supply of agates was exhausted 
they were sent there from other localities. 
That activity in this line began at a very early 
period we know from accounts of it which were given 
as early as the year 1497. Subsequently the industry 
declined, owing to the depletion of local supplies of 
agate, but the discovery of the Brazilian material re- 
vived it with great vigor and nearly all modern agate 
cutting, coloring, engraving, etc., is now done in this 
region. 
In carrying on this work, the rough agates are first 
broken with hammer and chisel into shapes approxi- 
mating those desired. These pieces are then some- 
what further shaped on metal wheels charged with 
emery or diamond powder, or they may be ground at 
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