Geology and Natxoral History. 81 



9. Analcite Rocks. — In a recent paper Mr. G. W. Tyrrell of 

 Glasgow University has shown that among the numerous intru- 

 sions of igneous rooks that penetrate the Paleozoic strata of the 

 west and south of Scotland there are numerous types of alkalic 

 nature, which are of interest to petrologists. Thus he describes 

 teschenites of several types, essexites, trachytes, etc., along with 

 other varieties. Among these in the south of Scotland are rocl<s 

 containing much analcite which, for several reasons, he considers 

 as a primary constituent. In a letter to the reviewer he says, in 

 addition, that "the group contains rocks of the analcite series 

 corresponding to the neplieline series, — from nephelite-syenite to 

 ijolite. The analcite syenite is a remarkably fresh rock composed 

 principally of soda-orthoclase, albite, and analcite, with purple 

 titanaugite, barkevikite, and aegirine. The latler is inclosed in 

 the analcite, which is very abundant. Another remarkable rock 

 is one composed principally of analcite, with a little nepheline, 

 crowded with perfect euhedral barkevikite, sometimes with a 

 little titanaugite and plagioclase." These appear to be remark- 

 able and novel rock types, and Mr. Tyrrell's forthcoming paper 

 upon them, in which full details are promised, will be awaited 

 with much interest by petrologists. — Trans. Geol. /Soc. Glasgow, 

 vol. xiii, Pt. Ill, p. 299, 1909. l. v. p. 



10. Morgan ite, a Rose-colored Beryl. — In a paper read before 

 the New York Academy of Science on December 5th, 1910, Dr. 

 George Ktjnz described some new and remarkable gems which 

 had been cut from a rose-colored beryl found in Madagascar. 

 He proposed the name morganite for them in honor of Mr. John 

 Pierpont Morgan of New York City. 



The beryl, together with other gem minerals, is found at 

 Maharita in the valley of Sahatonj^, an affluent of the Manandora 

 which passes along the western slope of Mount Bity, Madagascar. 

 The minerals occur in numerous veins of pegmatite which 

 penetrate the alternating layers of limestone, mica schist, and 

 quartzite. The veins often attain a thickness of nearly one 

 hundred feet and consist of quartz, amazonite often in fine colors, 

 albite, lithia, tourmaline, lepidolite in deep shades, etc. In these 

 veins magnificent crystals of tourmaline, beryl, and kunzite have 

 been found. 



The pink beryl, morganite, has also been found associated 

 with kunzite at Pala, San Diego Co., California, in large but 

 pale crystals and sometimes more of a salmon color. At the 

 Madagascar locality, however, it is found in magnificent speci- 

 mens of gem quality, some which weighed 98^ carats. Its color is 

 a true rose-pink, a pure, clear color with less of the magenta tint 

 than is found in even a pale tourmaline and lacking the lilac of 

 the kunzite. It is obtained in larger, finer stones than any other 

 pink gem mineral we have ever had. 



When exposed to the Rontgen rays the new beryl assumed 

 a brilliant cerise color under a tube of moderately low vacuum 

 with about twelve or fifteen amperes through the tube. When 



Am. Jour. Sci.— Fourth Series, Vol,. XXXI, No. 181.— January, 1911. 

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