In a paper dealing with the petrology of the cancrinite-ijolite from the alkaline massif of Iivaara in northern Finland, Lehijärvi (1956) described a nepheline with 19.8 atomic %K/(K + Na + Ca). The same nepheline sample was also used by Smith and Sahama (1954) in developing an x-ray method for determining the composition of natural nephelines. Another sample of nepheline that, according to a personal communication of Mr. Lehijärvi, originates from an exactly similar rock specimen (this Institute collection No. 9341) from the same locality, was investigated by single crystal x-ray methods. The result of this study is briefly summarized in the following.

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