Hookah charcoal is used to heat molassed tobacco to its boiling point, thus producing hookah smoke. Hookah charcoal is generally divided into two categories; quick-lighting and natural coals. The quick-lighting variety are most used in the US as a result of their quick lighting nature, while the standard natural coals are used more in the middle east.
The finest quick light hookah charcoal is the Three Kings brand. These coals are reknowned for thier easy lighting capability and long, hot burn.
A poorly made quick lighting coal will spark rather violently and go out almost immediately.
The most standard form of natural charcoal is the syrian finger coal. These coals are extruded under pressure to form a consistant round stick. This uniformity makes the charcoal very easy to light, even on an electric stove.
Un-lit fingers are placed on top of burning hookah charcoals while hot coals are pulled from the bottom to achieve a never ending flow of coals, once the initial charcoal is lit.
You are strongly advised against charcoal from a barbecue. When barbecue charcoal is compressed a variety of chemicals are added, and these should be avoided. Only ever use charcoal especially made for use in hookahs. If you buy good quality charcoal, you are sure you are only getting tightly compressed charcoal with no added chemicals.