sandstone - medium grained gray - 4" diameter oil well core section from the Stevens Sand sections up to three feet

sections up to three feet long are stored in core trays and boxes

The stripes are related to wind-mobilized grain flows while this sand was still in the dune field

The technology involved is impressive

We could have run it through a concentrator to increase the garnet content

Perlite ore ranges from gray to black

sandstone - medium grained gray - 4" diameter oil well core section from the Stevens Sand sections up to three feetOil well 4" diameter core section from the Stevens Sand, a prolific Upper Miocene oil producer in California's San Joaquin Valley. This medium grained sandstone is composed primarily of quartz with feldspar and some biotite. The Stevens sand is derived from the rapid uplift of the Sierra Nevada during the Miocene. A plug was occasionally removed from each core for determination of permeability and porosity of the sand. Well data has been lost for this