172 EARTHS. SILICEOUS. 56. Chalcedonius, 



Sardus* Pale, variegated with blood- red dots and drops. 

 Silex vagus, Syji. nat. xii. 3./'. 68. n. 5. 

 Caeneolus albefcens, WalLfyJi. i.p. 274. «. 14. f. 

 Sardoine. Schmeifser miner, i. p, iio. 



Found in India, Sardinia, near Oberftein in the Palatinate: co- 

 lour grey, or a little milky, rarely brown, 



dendriticus* Pale, painted with deeper-coloured arborefcent ramifica- 

 tions. Mocha J}one» 



Achates figuratus. Wall.JysL 1. ^. 285, «. 22. I. 



Found in the Ea/t, Iceland^ the Palatinate of the Rhine, and other 

 parts o^ Europe : colour white or grey with (hrub like black, 

 brown, red, or green pictures : thofe of the Eaft are elleemed 

 very valuable. 



piaculatus. Marked with fpots differing in colour and in degree of 

 tranfparency. 



Plafma. Thomfonchem* 'X^. p.^'i^i^ 'Jameifon min. i./. 189. 



Found in Ceylon, the Feroe ifiands, Italy, and the Palatinate: 

 colour wine-yellow with darker fpots, perlaceous or yellow- 

 ifh-brown with milk-white fpots difpofed in rings, milk- 

 white with black or red fpots, blood-red with biown or 

 white fpots, or grey, grafs-green, or olive-green variegated 

 with fpots of a reddifti or whitifh colour, 



fatciatuin Marked with bands differing in colour and degree of 



tranfparency. 



Sardonyx, Schmeifser miner. \, p. ill. 



Found in Ceylon, Feroe and Iceland, Bohemia and Saxony : colour 

 grey, fomewhat pellucid, with milk-white diaphanous bands, 

 rarely wirh thofe that are rofy or green, or blueiili or blood - 

 red with white or grey bands; the bands are narrower or 

 broader, of equal or unequal width, parallel, confluent, 

 ftraight, angular or undulate, 



Oftyx, Breaking into concentrically cruftofe fragments differing 



in colour and degree of tranfparency. 



Silex vagus. Syst. nat. xii. 3. p. 69. n. 7. 



Achates. WalUfy(l*inin, I. p, 276. n. 16. 



Onyx. Schmeijfer mineral. I. /. 108. 



Found in the Eaft Indies, Siberia, Bohemia, Portugal and Saxony, 

 in thicker or thinner fragments, and fometimes in pebbles: 

 colours grey and black, white flefh-colonr and black, red and 

 white, white and grey, various fhades ot yellow, alternating 

 in various manners, generally in concentric circles: it loles 

 its colour in the fire, and cracks and breaks if the heat be fud- 

 den or violent : it is the hardeft of all its genus : fpeciiic 

 gravity from 2,500, to 2,600. 



