In pearls, the nacreous layers are generally translucent and composed completely of aragonite, whereas layers without pearly luster are opaque and composed of aragonites and/or vaterites with their relative concentrations different in different pearls.
In pearls, the nacreous layers are generally translucent and composed completely of aragonite, whereas layers without pearly luster are opaque and composed of aragonites and/or vaterites with their relative concentrations different in different pearls.
其中具珍珠光泽的珍珠层一般呈半透明状，均爲文石组成；无珍珠光泽的不透明层有时由文石组成，有时由六方碳钙石组成。