Pearl∼珍珠 CaCo3+conchiolin, oragnic gem, a concretion consisting of concentric layers of an organic material (conchiolin) and crystalline calcium carbonate in the form of aragonite arranged radially around a small body as nucleus. 現有珍珠，大部份是以珠核，經人工培育而成的，所謂養珠，日本珍珠，以圓,大，光澤強，無瑕疵，且粉紅色者，最珍貴． 南洋珠較碩大，以孔雀綠，黃金珠最好． 淡水珠主要在中國大陸,為無核養珠，大都扁平，但已有圓形者． 霰石所形成之水波紋，為和人工仿冒品區分之重點． 珍珠為六月生日石．

@張盛弘
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