Cortinarius alboviolaceus is a basidiomycete mushroom of the genus Cortinarius native to Europe and North America. The mushroom is lilac, later yellowing and often becoming whitish/grayish. Its cap is 3–8 cm wide, conical to umbonate, dry, silky, with whitish to pale lilac flesh. The gills are adnate or adnexed, grayish lilac becoming brown as the spores mature and lend their color. The stalk is 4–8 cm tall and .5–1.5 wide, larger at the base, sometimes with white veil tissue. The odour and taste are indistinct.