A pearl nucleus that can avoid the danger of destruction of all RF tags by jewelry working； a relevant pearl； and a process for producing such a pearl nucleus. First and second RF tags (11,12) are embedded in the vicinity of surface (101) of nucleus substratum (100). The first and second RF tags (11,12) are disposed in positions not allowing facing with each other on straight line (X) passing through the center (c100) of the nucleus substratum (100). The pearl utilizing such pearl nucleus (10) has its surface (101) covered by pearl layer (30). There is provided a process for producing pearl nucleus (10), comprising the steps of making first and second setting holes (14,15) on nucleus substratum (100) so that the first and second setting holes (14,15) are disposed in positions not allowing facing with each other on straight line (X) passing through the center (c100) of the nucleus substratum (100)； fitting first and second RF tags (11,12) to the first and second setting holes (14,15)； and closing up the first and second setting holes (14,15) so as to attain embedding of the first and second RF tags (11,12).
