Plate 52 



1. Walker County, Alabama; hexahedrite; Ni-Co 5.94 percent, P 0.28 percent. Rhab- 

 dites, unetched — an example of so-called "relief etching." Many hexahedrites show a pro- 

 fusion of such rhabdites. 



2. Walker County. An area similar to figure 3, etched. Neumann lines are revealed, 

 and the rhabdites have sharp black outlines due to the strong attack of the etchant on inter- 

 faces. Picral; X 60. 



3. Walker County. Exceedingly fine and long schreibersite needles (lamellae), oriented 

 in three directions. Their orientation is different from that of the Neumann lines, one set 

 of which is faintly distinguishable. One lamella (upper right) is broken and slightly dis- 

 placed where it crosses the planes of two Neumann lines. Rhabdites and fine phosphide 

 particles. Picral; X 60. 



4. Sierra Gorda, Chile; hexahedrite; Ni-Co 5.83 percent. Parallel, thick needles of 

 schreibersite. Four sets of Neumann lines can be distinguished. Picral 200 seconds; X 60. 



172 



