EARTHS; SILiCEOUS. 55. Qiiartzum* 
16^ 
b. The pyramid double. Born.ind. l. tab. 2 . f, 
c. The pyramid regular. 
d. The pyramid with the alternate faces larger, 
e. The pyramid with one face larger than all the others. 
And. Br. a.d. Schnueiz tab. w.f. h. 
f. The pyramid with all the faces unequal, 
4; The prifms terminating at each end in a 6-fided pyramid not 
ftriate. Gmel. Jyft. not. 3. 445. i./l i . 
a. With the faces equal. 
b. With the faces unequal; 
5 - The prifms with ftraight margins. 
6. The prifms with all or fome of the margins twilled outwardly 
towards the bafe. isytt nat. xii. 3, p. 84. ». z, b, 
7. The prifms with all the faces unequal. 
8. The cryfttl folid. 
9. The cryllai hollow within. 
Nitruni inane. Stfi. nat, xii. 3. p. 85. k. 4. 
Aman.acad. )• ^.478. n, 14, tab- 16. f. iz. 
Wall.Jyli. min. 1, p, 218. n. g. d. 
a. The hollow of the cryftal empty. 
b; The hollow inclofing a bubble of air, i drop of waters * 
leller cryllai, or fome other foffile. 
10. The cryllai with a thicker prifm fcated on a thinner. 
iV». ind. foft, I. p. 22. tab. 2 . f-\- 
it. The thinner prifm with a double broader pyramid placed os 
it,' with 2 intermediate unequal globules. 
Born, ind, foft. 1. p. 23. tab. 2. f. 6. 
12. The cryllals folitary. 
a. Detached. 
b. United at the bafe. 
i 3, The cryllals in pairs or 3 together. 
L The bafe of the prifm of each cryllai coherings 
b. Pearl-like, cohering. 
c. Mutually perforating each other. 
14. Aggregate, Syst. «ar. xii. 3. p. 84. «. z. f, 
Atnotn. acad. \, p. 477 * tr. lt>. tab, 1 6, 6. 
a. In feries. 
b, Faickled. 
