著者

砂川 一郎

出版者

宝石学会(日本)

雑誌

宝石学会誌 (ISSN:03855090)

巻号頁・発行日

vol.9, no.2, pp.55-60, 1982

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Nambulite, LiNaMn_8Si_<10>O_<28>(OH)_2, and sugilite, (K, Na) C(H_2O), Na]_2 (Fe^<3+>, Na, Ti, Fe^<2+>)_2 (Li, Al, Fe^<3+>)_3 Si_<12>O_<30>, are two new minerals found and described for the first time in Japan. At the time of findings of the two minerals, no body imagined that these could be gem materials. But, recently, two minerals of gem quality have been found in Africa. Nambulite found at Kombat, Tsumeb, Nambia is deep red in colour and transparent, attaining 3cm in length, and cuttable as facet stones. Sugilite found in Wessels mine, Karahali manganese field, Cape Province, South Africa is violet in colour, and translucent, beautiful enough for cabochon cutting. This was at first reported as sogdianite, but later was identified as sugilite. Both are most unusual cases for new minerals found in Japan, and thus are introduced in this paper.