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.
Peridot is a gemstone from the mineral olivine. Like citrine, peridot is one of the very few gemstones that have only one color: green, though shades of the green gemstones range from olive green, to brownish, to almost yellow â all with glassy luster.hough popularly known for their white variety, pearls are also available as black, yellow and green stones. Light green pearls are produced by Japanâs Akoya oysters, while the dark green gemstones come from the black pearl oyster, whose pearls are not necessarily black, but may also be shades of green and blue.