82 EARTHS. CALCAREOUS. 12. Spatum. 



Found chiefly in limeftonc rocks in moft parts of Europe: colour 

 white, rarely yellowifli, pale brown, reddifh, green, very 

 rarely crimibn, blueifh, purple or black : never quite opake, 

 but ibmetiaies with a pearly Uiilre. 



culicum. With perfedly cubic aggregate cryftals. 



Spat, cryftal cubic. U^all.Jyst. 1.^.141. »,6. a. 

 Pearl fpar. Son.verby Brit, miner. 1. />. 45. /. 19. 

 Found in limeftone rocks, generally white, fomeiimes with a 

 pale rofy luftre, and cluftered together in various fhapes. 



rhombeum* With aggregate cubic cryftals, the faces of which are ob- 

 liquangled, 

 So<werby Rrit^ miner. I, p. g. tah,^^ 

 Systy nat. 1. p. 164. n. 4, tab. 8./", 13. 

 Aman acad. i. p 481. tab. \6.fig. 12. 

 Gmel. fyst. nat. 3. p 446, tab. i- fig. 22. 



2, Rhombic, with 2 oppofite obtufe margins truncate, 

 Karsten Lejke miner, i . />. 260, 



3. Rhombic, with the faces convex. 

 Kant en hejke miner, i. p.2^g. 



Found in many mines of Europe, among limcflone rock, and is 

 generally white, or reddifh from a mixture of iron, 



triedrum. With 3-rided prifms, terminated by a j-fided pyramid. 

 Porus prifmaticus. Qerh^ mineraU p./^j, 



tetraedrum. With 4-fided prifms. 



Born^ ind,fofs. I. p,6t 8. 2. p» yiJ. 



2. Prifmatic, with the alternate faces narrower. 



3. With the furface rugged. 



4. Prifmatic, with the terminal faces running into an acicular 



point. 



5. The prifms terminated at each end by a 3-fided pyramid. 



Found in the mines of Scotland near Strontian, in Sile/iay Huti- 

 gary. Saxony , and other places, fometimes opake, fometimes 

 pellucid, frequently white, rarely reddifh or greenifli. 



prismaticum With perfedly 6-fided prifms. 



Gmel. fyst. nat. 3. p. 445. tab. I. f, 5. 



Nitrum iruncatum, Syst- nat, xii. 3. /). 86. n, 5. 



Cryltallus fubnitriform, Amccn. acad. 1. p, 497. /. 16./. 16. 



Spatum cryflallizatum. Wall. min. 58./. 5. 



2. Prifmatic, with the terminal faces convex. 



3. With the terminal faces ending in an acicular point. 



4. Prifmatic, with the alternate faces narrower. 

 Gmel fyft^ nat. 3, />. 445. tab. i. fg, 6. 

 Crydaiius fubnitriformis. Jmain^ acad, i. p. A-7^' 



