The Coquihalla Serpentine Belt forms a narrow, elongate north- northwest trending, steeply dipping unit separating supracrustal rocks of the Lower-Middle Jurassic Ladner Group to the east, from the Permian-Jurassic Hozameen Complex in the west. Dark, highly sheared to massive serpentinite of probable peridotite parentage, characterizes the belt. It also contains substantial amounts of highly altered gabbro-diabase rocks.

The western boundary is delineated by a major fracture which appears to dip steeply east. This is termed the "West" Hozameen fault and the serpentinites in this vicinity contain highly sheared talcose rocks. The "East" Hozameen fault separates the serpentinite from the Ladner Group metasediments.

Tiny veinlets of asbestos (chrysotile) are commonly observed in hand specimens of the serpentinites. Under microscopic examination, this serpentine has been identified as antigorite, but varies considerably in appearance according to the stage or amount of serpentinization under which the rock was submitted. Also, thin, bluish white and rather pearly films of another type of serpentine, somewhat resembling chrysotile, commonly coat fractures or joint planes within the rock.

Talc is extensively developed along shear zones in and bordering the main serpentinite body and is also associated with carbonate in more massive bodies within the serpentinite.