Process manufacturing produces co-products and by-products. A co-product is a saleable end item that results from a process. A by-product is a material of value that is produced incidental to or as a residual of the process.
D. a rock with metamorphic minerals but no foliation or lineation. A shale is metamorphosed into three rock types: (1) a banded gneissic rock; (2) a rock with small mica crystals with a shiny aspect; (3) a very shiny rock with large mica crystals; and (4) a dull slate with cleavage. Which of the following lists these rocks in order of increasing metamorphic grade?
EDIT: From The Straight Dope: The truth is that the shiny side is not treated with a dangerous chemical. Mineral oil is used as a lubricant during the rolling process, some trace of which may remain on the finished foil--but it's not dangerous. The shiny side is shiny because of the way foil is made. During the last pass through the rolling mill, a double thickness of foil is run between the rollers. The side of each sheet that comes in contact with the polished steel rollers comes out shiny. The other side has a matte finish.