MINERALOGY. $$ 



enough or in fuch quantity as is necefiary for 

 experiments to be made. 

 F. The yeilowiih green and cloudy topaz, the 

 Cbryfcprafe. 



This is perhaps the fubftance which ferves 

 as a matrix to the chryfolite : for thofe I 

 have feen of this kind are like the clear- 

 veined, called in Swedifh milk criftal, and 

 quartz, which is of the firft degree of crif- 

 tallifation. 



SECT. XLVII. 



E. Bluifh green topaz, or the Beryll. 



This varies in its colours, and is called, 

 when 



i. Of a lea-green colour, the aqua marina. 

 2. When more green, the Beryll. 



They are found in the ftream-works 

 in Saxony and Bohemia, in form of peb- 

 bles, or round pieces. 



SECT. XLVIIL 



D. Emerald. Smaragdus gemma. 



Its chief colour is green, and is tranfpa- 

 rent. I believe it to be, or to have been, a 

 cnilal of its own feparate principle, fince 

 in its qualities it differs both from the 

 above-mentioned, and from the rock-crif- 

 tals , but I cannot pofitively alTert this, 

 fince I know no more of it, than that it is 

 the fofieft of precious (tones, and that, 



ben heated, it is phofphorefcent, like the 

 fluors ; and what in fome cabinets is given 

 oat for its matrix, and laid to comcMrorn 

 Egyp:, is nothing elfe than a deep green 



E 3 cockle 



