延性符号 meaning in English

sign of elongation

Both the methods for measuring such optical constants as cleavage angle , interference color level , extinction angle , length sign , optical sign , optic angle , pleochroism formula , absorptivity formula and the determining program for transparent minerals will be emphasized to lecture
重点讲授透明矿物解理夹角、消光角、延性符号、干涉色级序、光性符号、光轴角、多色性公式、吸收性公式的测定方法和透明矿物的鉴定程序。