Geology and Mineral Resources of Paraguay A Reconnaissance

48 GEOLOGY AND MINERAL RESOURCES OF PARAGUAYFIGUEE 38. Shonkinite (specimen P-54c) from Mbocayaty is similar to sample P-54a (fig. 36) but shows abundant hydronephelite, ft. The large grainswith good cleavage are pyroxene, p; another large grain, o, showing a few fractures but no cleavage is olivine; k, is kataforite amphibole: and orthoclase,/, is myrmekitic replacement of hydronephelite. The black areas are brown biotite, ft, and opaque ore grains. X 15.FIGURE 39. Shonkinite (specimen P-54d) from Mbocayaty. Aggregate of orthoclase, /,- pyroxene, p; hydronephelite, ft; magnetite-ilmenite ore, o.biotite and brown hornblende are sparse. X 15.Brown