172 Count de Bournon’s Description of 
uneven, as if composed of small laminae, crossing one another 
in an irregular manner. When it begins to decompose, its sur- 
face is covered with the most beautiful colours ; among which 
the most predominant are, violet, blue, and green : this has 
caused it to be compared to a pigeon’s breast. When these 
colours are very deep, and occupy the whole surface of a piece, 
we commonly perceive here and there, some little points, in 
the state of red oxide of iron ; and others of a green colour, in 
the state of green carbonate of copper. 
This kind of copper ore is sometimes of a deep yellow 
colour, which inclines the more to green, as it is destitute of 
brilliancy. It is very compact, and, when broken, the fracture 
appears smooth, sometimes a little conchoidal ; its surface, how- 
ever, has a very fine grain, which, when viewed with a powerful 
lens, resembles the aggregation of a very close compact mass of 
the finest sand. Its most usual texture is that of thin layers or 
plates, lying one upon another, and being very closely united, 
so as to be scarcely perceptible to the naked eye; but they 
are very readily distinguished with the lens. These layers, 
however, do not adhere very strongly, as they may always be 
separated by the stroke of a hammer. 
This ore frequently assumes a mamillated form; the ma- 
millae being of different dimensions, from the size of a man’s 
head, and even larger, to that of a small pea. In the latter 
case, the mamillae are very often united, as in that kind of iron 
ore which is called cluster, botryoid, or kidney hematites. Some- 
times the surface of the mamillae is covered with small points ; 
but more frequently it is smooth, so as very much to resemble 
a piece of polished metal ; and, as the surface of the mamillae 
inclines rather to a brown colour, they have the appearance of 
