Rice Krispies

The cockscomb pearl mussel, Cristaria plicata, lives in Japan and China. It produced the original rice-krispie pearls. They were small, irregular in shape, and had a wrinkled appearance. They were naturally white, but were frequently dyed. The mussels have thin shells and, when pearl cultivation was first attempted in China, were proved to be incapable of producing freshwater cultured pearls of high enough quality. 

The triangleshell pearl mussel, Hyriopsis cumingii, is the oyster now used in China to produce their freshwater cultured pearls, which are of a vastly superior quality to their original rice-krispies . The triangleshell is also farmed in Japan. It has a much thicker shell than the cockscomb, and it can produce nearly perfect round pearls with a good lustre. The naturally coloured nacre occurs in whites, orange-browns and blue-greys. White is the most popular colour (Fig. 9.5). 

The original attempts at Chinese pearl cultivation produced pearls which were relatively small and wrinkled. They were generally referred to as rice krispies after a well-known breakfast cereal of a similar shape. Nowadays much better quality non-nucleated cultured pearls are produced in China (Fig. 9.5). 

Fig. 6.4-20 a) Growth agglomerated cereal mixtures b) "Rice Krispies (courtesy Kellogg Co., Battle Creek, Ml, USA)... 

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