2004年,坦桑尼亚发行了一套题为《坦桑尼亚矿业》的邮票,由4枚邮票、1枚小全张和1个小型张组成,其中小型张邮票的图案展示了六种未经加工的宝石,即宝石矿物原石,分别是变石(也叫金绿宝石)、金刚石、红宝石、绿宝石、坦桑黝帘石和蓝宝石。在这枚小型张邮票上标注的文字出现两处错误,一处是右上角的“Unprossed gemstones of Tanzania” (未经加工的坦桑尼亚宝石),其中 In 2004, Tanzania issued a set of stamps entitled “Tanzanian Mining,” consisting of four stamps, one souvenir sheet and one sheetlet, in which the pictorial postage stamp shows six types of unprocessed gemstones, That is, gemstones, which are metamorphosed (also known as emerald), diamond, ruby, emerald, tanzanite, and sapphire. There were two errors in the text on the miniature stamp, one at “Unprossed gemstones of Tanzania” in the upper-right corner, of which