基础英语演讲--钻石diamond.ppt

diamond Diamonds are made from carbon.It is a polymorph(同素异形体) of carbon.The other form is graphite（石墨）. time;very high tempreture(around 1000 degrees);very high pressure(above 30 kilobars(kb). The first area was india, where diamonds were found thousands of years ago. In 1720’s ,diamonds were discovered in Brazil. In the 1800’s , two other important areas were found in Russia and South Africa. Some diamonds are found in stream beds.People would pick up handfuls of gravel from the bottom of the streams and sort out of the diamonds. Most of diamonds today are not found in stream bed.They are mined from rock formations deep inside the earth called pipes. South Africa Kimberley Mine(also named Big Hole) Depth : 1097 meters Russia 俄罗斯西伯利亚米尔钻石矿坑 The biggest one:Cullinan from South Africa shape 公主方型 榄尖型 椭圆型 梨型 心型 ?祖母绿型 圆型 A Diamond Is Forever “Diamonds are forever .”it is often said .But lives are not .We must spare people the ordeal of war ,mutilations and death for the sake of conflict diamonds. Blood Diamond In relation to diamond trading, blood diamond (also called a converted diamond, conflict diamond, hot diamond or a war diamond) refers to a diamond mined in a war zone and sold to finance a rebellion, invading armys war efforts, or a warlords activity, usually in Africa. During 1990’s,diamonds fueled the civil war in Angola with terrible consequences.In 1999,the UN security Council acted to enforce sanctions(制裁) on diamond sales by the rebel groups and the conflict finally ended a short time. But since then ,further diamond-related conflicts have raged in Sierria Leone,Liberia,Ivory coast and the democractic of Congo. The Worldwide Diamonds Prducer Angola Angola formerly a colony of Portugal gained independence in 1975.Although independent ,the Popular Movement for the Liberation of Angola(MPLA),the National Union for the Total Independence of Angola(UNITA) and the National Liberation Front of Angola(FNLA) fought in civil war from 1975 to 2002. UNITA