/PRES-MTN12-12B-3L-1_4x_ppl_49cm_sand-200s.jpg "Iron Oxides, Opaque (e.g., magnetite)")
/PRES-MTN12-12B-3L-1_4x_xpl_49cm-200s.jpg "Iron Oxides, Opaque (e.g., magnetite)")
/PRES-MTN12-12B-3L-1_ppl_4x_53cm_sandy-200s.jpg "Iron Oxides, Opaque (e.g., magnetite)")
/PRES-MTN12-12B-3L-1_xpl_4x_53cm_sandy-200s.jpg "Iron Oxides, Opaque (e.g., magnetite)")
/calcite_ironoxide_40x_opaque_pp-200s.jpg "Iron Oxides, Opaque (e.g., magnetite)")
/calcite_ironoxide_40x_opaque_cp-200s.jpg "Iron Oxides, Opaque (e.g., magnetite)")
Description
Fully opaque where visible by light microscopy. In coarser, sorted lacustrine sediment, cubic, faceted, or irregularly blocky grains may occur in association with other high-density minerals. May be distinguished from pyrite and other sulfides by grey color under oblique reflected light. Biomineralized magnetite produced by magnetotactic bacteria is widespread in sedimentary environments, but normally in a sub-micron size class well below that of grains discerned in smear slides.
Fully opaque where visible by light microscopy. In coarser, sorted lacustrine sediment, cubic, faceted, or irregularly blocky grains may occur in association with other high-density minerals. May be distinguished from pyrite and other sulfides by grey color under oblique reflected light. Biomineralized magnetite produced by magnetotactic bacteria is widespread in sedimentary environments, but normally in a sub-micron size class well below that of grains discerned in smear slides.
External Resources