The CAL A quarry is situated on a north-facing ridge side south of Deserted Lake and east of Hisnit Inlet, 32 kilometres west of Gold River, B.C. It is accessed off the Head Bay Forest Service Road between Gold River and Tahsis. It lies 500 metres northeast of the operating Matrix Marble Quarry (092E 020).

CAL A is one of the several marble showings / quarries within Callache Stone Quarries Inc.'s Tahsis property, including the Nootka Quarry, the CAL B showing, the Century Limestone showing and the Tlupana Arm magnesite showing. The Triassic Quatsino Limestone Formation on the property wraps around an Eocene Quartz Diorite Stock situated in the south of the peninsula between Hisnit Inlet and Tlupana Inlet (Head Bay).

In 2016 and 2017, logging road rehabilitation, overburden stripping and initial bulk sampling have exposed an area of approximately 1.7 ha. of semi-continuous bedrock, consisting of approximately 95% marble and 5% intrusive dikes. The marble varies in colour from white to grey, in grain size from fine to medium, and locally contains banding or layering generally striking northwest and dipping moderately to the northeast. The intrusive dikes are dark green in colour, fine grained, apparently intermediate to mafic in composition, average 1 m. in thickness, are irregular in shape but generally west-striking and steeply north-dipping, and are spaced approximately 20 metres. apart. Callache has assigned names to various styles of marble including “Acadia White” and “Victoria Blue”. Test work on CAL A, in the form of 216.5 metres of E-size diamond drilling in 13 holes, was also conducted in 2017 (Assessment Report 36511).