Xylene (derived from the Greek word for wood) is an odoriferous hydrocarbon. Essentially, it is a benzene ring that has a couple of methyl substituents. The 3 isomeric xylenes all possess the molecular formula C8H10, although C6H4(CH3)2 -- the semi structural, more informative formula -- is commonly used as well.
Xylene is a major petrochemical, created via coal carbonization during coke fuel manufacturing, and by catalytic reforming. Roughly, it represents 0.5% to 1% of crude oil (based on the source), and it is discovered in small amounts in airplane fuel and gasoline. Primarily, this petrochemical is created from BTX aromatics (toluene, xylenes and benzene) taken from the end result of reformate (the process of catalytic reforming).
This chemical is an oily, colorless fluid that comes in solvent form, most of the time. In 1851, it received its' name after it was discovered as a wood tar constituent. Millions of tons are created each year.