The year is divided into a dry and wet season, the first from June to December, when rain rarely falls, the streams dry up and the cameos are burned bare, and the second from January to May when the rains are sometimes heavy and the cameos are covered with luxuriant verdure.
Sao Paulo is partly covered by open cameos, and these also serve to augment the maximum temperature.
It contains 1300 great pearls, 400 garnets, 90 amethysts, 300 sapphires, 300 emeralds, 15 rubies, 75 balas rubies, 4 topazes, 2 cameos; the gems, except where they have been replaced, are cut en cabochon.
The plateau is less densely wooded, but has some highly fertile plains, the open cameos being partly devoted to stock raising.
Several of the varieties are cut into gems and ornaments, balance weights, pivot supports for delicate instruments, agate mortars, &c.; or used for engraving, for instance, cameos and the elaborately carved crystal vases of ancient and medieval times.