Palo Duro Canyon typical in-situ
Most hematite cones eventually weather out of the rock
intact. When they do they litter the ground, looking like "rhino
This one, occurring in medium grained sandstone, has a typical cone
apex angle. In very permiable clean sandstone they are
sometimes very narrow. In dirty fine grained sandstone they
usually are broader with a 45 to 90 degree apex.
Polished microscope sections and crossections show the hematite is
deposited in concentric rings with most of the
hematite in the outer rings. The hematite is deposited as a
cement, it does not replace the sand grains themselves.