The oil which occurs naturally in porous rocky strata in liquid form is the crude oil. If it is in semi hard state mixed in sand then it is bitumen. The crude oil can be black, brown, green or even orange to yellow. It contains oxygen, sculpture, nitrogen and other items in minute quantities which determines it suitability for a specific application. The crude oil or its derivatives are marketed by weight (by metric tons MT) or by volume (by gallon, liter or barrel). The co-relation between 7.2 to 7.4 barrels to 1 MT is taken for rough calculation only as is it not precisely accurate. Aviation Kerosene is roughly 7.8 bbls per MT. The price of Crude Oil is continually moving upward and this trend is unlikely to change as available volumes diminish. Most Sellers are reluctant to offer SPOT deals as they prefer their business Contracts to be continuous, with regular monthly shipments and yearly renewable.