【摘要】 湖北鄂州是中国淡水无核养殖珍珠的重要基地之一。通过对该产地无核珍珠表面形态、瑕疵、剖面和“勒腰”的显微特征的研究 ,认为“勒腰”主要分布在直径为 4mm以上的椭球状珍珠上 ,呈规则、直线状 ,在同一粒珍珠上“勒腰”相互平行 ,不交叉 ,钉状纹的朝向完全相同。扫描电镜显示 ,在“勒腰”部位文石层变碎、变薄 ,向下弯曲。如果文石层间隔性地缺失 ,则“勒腰”为一 U形沟 ,文石层仍连续分布 ;如果文石层完全缺失 ,则“勒腰”为一陡壁沟 ,在沟壁处文石层的有序现象完全消失。珍珠“勒腰”的形成可能与珍珠囊局部的分泌能力丧失且珍珠相对珍珠囊转动有关。更多还原

【Abstract】 The studied specimen of freshwater cultured non- nucleated pearls are taken from Ezhou City,Hubei Province,which is one of the important pearl- cultured bases in China. Studied by microscope on the shape,surface flaw,section and“Leyao”—— a ditch- like charac- ter on the surface of pearl,the“Leyao”is regular straight line- like,parallel to each other and usually found on surface of the pearls with diameter more than 4mm and oval shape resulted from rotated growth,accompanied by nail- like lines with same direction.It can be observed under SEM that the aragonite layers become thinner and cracked,and curve down from the normal to the“Leyao” part. The“Leyao” is a U- like ditch on the section and the aragonite lay- ers are continued on the wall of ditch if a intervallic lack of aragonite layers.The“Leyao”is a precipitous wall and aragonite layers are in disorder on the wall if aragonite layers are lack com- pletely.The“Leyao”is possibly related to the lack of secrete ability of pearl sac partially and pearl- rotated growth relatively to pearl sac.更多还原