[6] It was discovered in 1896 and named after Dr Richard Pearce (1837–1927), a Cornish–American chemist and metallurgist from Denver, Colorado.

[4][5][7] Unit cell parameters The crystal structure consists of sheets stacked along the c axis.

The arsenic atoms form isolated (As,Sb)S3 pyramids, copper cations link two sulfur atoms and the silver cations are found in various sites with low coordination numbers, 2,3 and 4, as is usually the case with silver.

[9] Pearceite is often granular and massive;[3] crystals are short, tabular pseudohexagonal prisms with bevelled edges, showing triangular striations on faces parallel to the plane containing the a and b axes, and rosettes of such crystals, to 3 cm across.

[4] The mineral is black, and in polished section it is white with very dark red internal reflections.

[3][4][5][6] The type locality is the Mollie Gibson Mine, Aspen, Aspen District (Roaring Fork District), Pitkin County, Colorado,[6] where the mineral occurs in hydrothermal deposits formed at low to medium temperatures, associated with acanthite, tetrahedrite, native silver, proustite, quartz, baryte and calcite.