Standard Briquets: These briquets are made by mixing borax, limestone, sodium nitrate, starch, anthracite coal, lignite car, sawdust and wood char with starch and a moistening agent. The ingredients are mixed to form a paste and the paste is then injected into briquet molds. Once the briquets are formed, they are dried in a n oven, packed and shipped. Cowboy doesn't carry these types of briquets.
100% Natural Hardwood Briquets: Hardwood briquets utilize a similar manufacturing process to composition briquets, but only contain 100% natural hardwood charcoal pieces and vegetable starch as a binder. These briquets deliver the high heat associated with lump charcoal and a longer burn than standard briquets. Try Stubb's.
Lump/Chunk Charcoal: Lump/chunk charcoal is manufactured from various species of hardwoods such as Hickory, Oak or Mesquite. Chunks or pieces of wood are slowly cooked in a high-heat environment to become carbonized wood. When used for grilling, lump charcoal will produce hotter temperatures and impart an authentic wood flavor to grilled foods. Try Cowboy Lump Charcoal.
This blog explains these charcoal types in more detail.