i 5 3 tremities of the acuminatiofis deeply truncated, big. 56. .ix-ftded prifm, having terminal edges and angles truncated. tourmalinf. Fig. 57. Equiangular threefided prifm, acumin ated on both extremities by three planes, which ml one extremity are let on the lateral planes, on the other on the lateral edges; and the lateral edges are fo deeply bevilled, that it appears like a nine-fuled prifm. Fig. 5K Flat, double three-fidt-d pyramid, in which the alternate angles, the common bafts, and - all the edges, are truncated. THUMERSTONE. Fig. $9. Very oblique rhomb, in which the two oppofite obtufe lateral edges are truncated. ROCK CRYSTAL. Fig. 60 Equiangular fix-fided prifm, fomewhat acutely acuminated on both extremities by fix planes, which are let on the lateral planes. Fig. 61. Double fix-fided pyramid. PREHNITE. Fig. 62. Oblique four ftded table. Fig 6p Same figure, truncated qn the acute edges. Fig. 64. Flat four-ftded prifm, bevilled cm both extremities, the bevilling planes fet on the fmaller lateral planes, and the edge of the bevillment truncated. RADIATED ZEOLITE. Fig. 65. Broad reflfangular four-fided prifm, a- cutely acuminated by four planes, which are fet on the lateral edges, and the extremities of the acutm- pations {lightly truncated. ■ a K Fl S- 66 •