Page:Popular Science Monthly Volume 69.djvu/279

Rh several carats in drying. It is of finest quality and almost rectangular shape. The equivalent of $26,400 was offered for it six months ago, but the owner has set a price which to-day is the equivalent of $45,625, an impossible figure, as in breaking there is always considerable loss. When carbon advances beyond a certain figure the sale of necessity decreases, as then there are other products which are used even though lacking in durability and other desirable qualities.

The genesis of the diamond and carbon has not been worked out for this section. Whatever it proves to be, it is certain that at one time they were all confined in a conglomerate which shows evidence of being of more recent geological date. The conglomerate differs in character in the different sections. In the neighborhood of Lavras Diamantinas it consists of many colored water-washed pebbles and boulders, chiefly sandstone of the same nature as the strata found immediately below it; in the Salobro region it consists chiefly of granite pebbles. In both instances the matrix is sand of different degrees of hardness, fineness and color.

With the ages a great part of the conglomerate has disintegrated and the rains and rivers have washed the diamonds and carbons to the places where they are now being found. There are large masses of conglomerate in many places which have resisted this action, and unless mechanical means are brought to bear will continue to yield diamonds and carbons for the ages during their disintegration.

The region about Salobro is comparatively flat, in fact the greatest deposit occurs in an area practically level, doubtless the old river bed. In the other sections of Bahia the country is rocky and mountainous. There is so much of rock and so little of soil that only small plants grow, and then only during the rain time. In some cases the rivers pass through gorges cut into the solid rock and most precipitous and awe-inspiring. On all sides there is much of interest. The rock formation is a very hard reddish sandstone which completely underlies the conglomerate and like it shows the disintegrating effects of water and climate. In places it has deep cracks which have become natural canals, accumulating with the ages a concentrated diamond-and carbon-bearing gravel. In other places immense pieces of sandstone and conglomerate are piled up heterogeneously as if they had been dumped there. The canal Simplicio Braga is a combination of these two varieties and was one of the richest finds of the region.

The diamond section of Bahia is much more accessible than that of Minas Geraes. One can arrive at Andarahy, the heart of the region, in four days from Bahia City, five hours of one clay being spent in journey by boat, twelve hours of the next by train and two days by mule. The trip is without hardships to one accustomed to travel. It is along attractive scenery, across rivers and mountains, passing through a section with beautiful calcareous caves, but with an entire