DEPARTMENT OF MINERALOGY. 163 



Department of Minerai.ogy. 



Research. 



During the past year the morphological and optical 

 investigation of the new red silver minerals from the 

 Binnenthal, Switzerland, has been completed, and a full des- 

 cription of the physical and chemical characters of these 

 species has been prepared and published. 



A large series of mineral -specimens from the new lead and 

 zinc mines at Broken Hill in North- Western Rhodesia has 

 been examined. Sixteen species of minerals have been deter- 

 mined, and a detailed physical and chemical investigation 

 has been made of various phosphates of zinc, including 

 hopeite and two new species which have been established, 

 viz., parahopeite and tarbuttite. 



The chemical examination of the new mineral striiverite 

 has been continued, and its relation to ilmenorutile has been 

 the subject of investigation. 



Various minerals formed during the eruption of Vesuvius 

 in April 1906 have been examined. In this connection the 

 crystallographic and optical constants of the new mineral 

 chlormanganokalite have been determined, and chlornatro- 

 kalite has been proved to be a mixture of sylvite and halite. 



The crystallographic examination of minerals from 

 Bolivia has been continued, and descriptions of many species 

 have been prepared for publication. 



I Various minerals from Cornwall, including phenakite, 

 anglesite, caledonite, heulandite and fahlerz, have been 

 examined and determined. 



Crystallographic measurements have been incidentally 

 made on various other species, including idocrase, kunzite, 

 monazite, schwartzembergite, sylvanite, seligmannite, ten- 

 nantite, thorite, topaz, whewellite and zircon. 



In the course of a critical examination of the faceted 

 stones in the Collection, the refractivity has been determined 

 of specimens of sapphire, ruby, emerald, aquamarine, phena- 

 kite, beryllonite, hiddenite, kunzite, chrysoberyl, olivine, 

 quartz, axinite, andalusite, epidote, euclase, diopside, idocrase, 

 opal, hessonite, pyrope, cordierite, enstatite, tourmaline and 

 benitoite. 



Specimens of " re- constructed" ruby and spinel have been 

 optically and chemically examined. 



. A microscopic examination has been made of a collection 

 of 280 rock-specimens from South Africa. 



0.109. M 



