The outer portion (1.5mm to 5mm) of the cerebrum is covered by a thin layer of gray tissue called the cerebral cortex. 1  The cerebral cortex is in turn divided into four lobes: frontal lobes, parietal lobes, temporal lobes, and occipital lobes. The cerebrum or telencephalon, along with the diencephalon comprise the two major divisions of prosencephalon (forebrain).
Gemstones from Africa. The traditional sources for colored gemstones are in Asia and South America, especially Burma, Sri Lanka and Brazil. However, these days Africa is generating most of the the excitement in the gemstone world.Looking at our own inventory of over 35,000 gems, about 50% of them originate from Africa.owever, these days Africa is generating most of the the excitement in the gemstone world. Looking at our own inventory of over 35,000 gems, about 50% of them originate from Africa.
Although Colombia is the most famous source for 'deep green' emeralds, emerald deposits are mined from many locations around the world. Recent decades have seen emerald production increase as a result of newly discovered deposits in South America, Africa and across Europe.merald is the most precious stone in the beryl group. The name comes from the old French word 'esmeralde', which was derived from the Greek word 'smaragdos' meaning 'green stone'. By definition, emerald is any medium to dark green beryl colored by chromium.