DIAMOND. 23 
mill, the opposite end of the stick to which it is ce- 
mented being inserted in one of the holes of the guage. 
In this position it is kept steady by the workman, with 
his right hand, whilst, with the other, he puts the mill 
in motion. The skill of the lapidary depends on regu- 
lating the velocity of the mill, and pressing with more 
or less force on the stick, with an almost imperceptible 
tendency to one or other direction in different stages of 
the work, examining each facet at very short intervals, 
in order to give as great precision as possible to its size 
and form. This part of the business being completed, 
the cutting mill is taken out, and replaced by one of 
brass, on which the polishing is performed by means of 
fine emery (58), tripoli, and rotten stone (119), exactly 
in the same manner as is practised in the first stage of 
the process for setting the facets. 
DIAMOND. 
50. The DIAMOND, or ADAMANT of the ancients, is 
the most valuable of gems, and the hardest of all known bodies ; 
when pure, it is perfectly transparent. 
In a rough state, diamonds have usually either the form of 
rounded pebbles, with a shining surface, or they are crystallized 
in the shape of octahedrons, or double four-sided pyramids. 
(Fig. 5, 6.) Though for the most part colourless, they are 
sometimes yellow, green, blue, blackish, or rose-coloured. 
The best diamonds are brought from the East Indies. 
The principal mines are those of Haolconda and Cou- 
lour, in the province of Golconda ; and that of Soumel- 
pour, or Goual, in Bengal. At Raolconda they are 
found in the deep crevices of rocks. Persons, by 
means of long iron rods, with hooks at the end, draw 
out from these crevices the loose contents, and after- 
wards wash them in tubs, for the purpose of discovering 
the diamonds. 
The first discovery of diamonds at Coulour was about 
two centuries ago, by a countryman, who, on digging 
his ground to sow millet, accidentally found one of 
these stones of large size. From that period the whole 
