龙纹青花敞口瓶，大清雍正年制款，敞口，宽颈，圆肩，圆腹上衬，圈足。足内白釉泛青，此瓶正反两面描绘五爪祥龙翱翔海天，辅以云纹萦绕，足底显大清康熙年制六字两行款。青花瓷是古瓷中的佼佼者，以景德镇所产的为代表。它是以钴料为着色剂，在白胎上绘画，再施一层透明釉，经上千℃左右高温焙烧的釉下彩瓷。由于其生产工序简便，一次烧成，青花色调清新明快，素雅大方，经久耐看，加之为釉下彩瓷，画面不易磨损，无铅无毒，因而被广泛使用。 A dragon pattern blue and white wide-mouth vase with Da Qing Yong Zheng mark on bottom. It features dragon pursuing flaming pearl on sides. Demensions are: 18 inches tall X 9 inches in diameter."Blue and white pottery" covers a wide range of white pottery and porcelain decorated under the glaze with a blue pigment, generally cobalt oxide. The decoration is commonly applied by hand, originally by brush painting, but nowadays by stencilling or by transfer-printing, though other methods of application have also been used. The cobalt pigment is one of the very few that can withstand the highest firing temperatures that are required, in particular for porcelain, which partly accounts for its long-lasting popularity. Historically, many other colours required overglaze decoration and then a second firing at a lower temperature to fix that.