M I N E RALOGY. *£; 



There hm Europe great quantities of 

 moft varieties of agates *, particularly at 

 Oberftein in the. Palatinate, where they 

 are cut and polifhed : but they are like- 

 wife found in every part of the world. 

 In Sweden there is not yet, as far as I- 

 know, more than one fpecies of agate 

 found -, namely, at Gafebeck, in the pro- 

 vince of Skone, which is of a white and 

 deep red colour. 



SECT. LXII. 



S. Common Flint, Silex communis Pyrmna- 

 chtts. 



Is really of the fame fubftance as the 

 agate -, but as the colours are not fo flriking 



* I have lately got a fpecimen of a hollow agate ball, with 

 pale amethiils in the infide, between which is cryftallifed a 

 calcareous fubftance into a fibrous form. Thefe fibres are 

 parallel, white, mining, and very minute, exactly refembling 

 the fineft albeit, for which it alfo might be miftaken, if it was 

 to be judged only by the eye. But by experiment it is found 

 neither to be an afbeftus nor a gypfum, which fometimes 

 moot alfo into a fibrous form, but entirely a pure calcareous 

 fubftance. The whole mafs does not adhere together, but 

 is nearly divided into fmall triangles, which are placed upon, 

 one another, fo as almoft to form a large figure of the fame 

 kind. TKefe fibres however, although very minute, may be 

 found by means of a proper manifying-glafs v to be of an 

 angular figure, like thofe mentioned in the note at page 82. 

 Tne fhape of balls and irregular nodules, is the moft general 

 f rrn in which agates and flints are commonly found, Neverthe- 

 lefs, befides what I have feen in feveral collections in London 

 and abroad, I have likewife fome fpecimens of native filver, 

 from Potofv.n the c pinim Weft Indies, which run in a grey 

 and h t agate, with white opaque veins ; which 



feerni to confirm the" opiflidn, that agates may form veins in 

 rock-, as v f-11 as other forfs of ftones. [See the note of 



•ft. LXHL] E. 



